Optical node device, network control device, maintenance-staff device, optical network, and 3R relay implementation node decision method

ABSTRACT

An economical optical network is constituted by effectively using network resources by using the minimum number of, or minimum capacity of 3R repeaters. 3R section information corresponding to topology information on the optical network to which an optical node device itself belongs is stored, and the 3R section information stored is referred so as to autonomously determine whether or not the optical node device itself is an optical node device for implementing the 3R relay when setting an optical path passing through the optical node device itself. Alternatively, when the optical node device itself is a source node, another optical node device for implementing the 3R relay among the other optical node devices through which the optical path from the optical node device itself to the destination node passes is identified, and this identified optical node device is requested to implement the 3R relay when setting an optical path in which the optical node device itself is a source node.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. patent application Ser. No.12/255,923 filed Oct. 22, 2008 which is a divisional of U.S. patentapplication Ser. No. 10/531,507 filed Apr. 14, 2005 which is a NationalStage of International Application No. PCT/JP2004/003301 filed Mar. 12,2004. Priority is claimed on Japanese Patent Application No.2003-069216, Japanese Patent Application No. 2003-069223, JapanesePatent Application No. 2003-069233, and Japanese Patent Application No.2003-069246, each filed Mar. 14, 2003. The entire disclosures of each ofthe above applications are incorporated herein by reference.

TECHNICAL FIELD

The present invention is used in optical networks that switch opticalsignals. In particular, the present invention relates to opticalnetworks including optical node devices that implement 3R (Reshaping,Retiming, and Regenerating) relay.

BACKGROUND ART

In an optical network, it may be necessary to provide 3R relay partwayalong an optical transmission path, in consideration of deteriorationand loss in the fiber, and crosstalk. FIG. 87 shows a conventionaloptical network configuration. In order to provide 3R relay, 3Rrepeaters 1002 are inserted into each optical node device 1001 providedpartway along an optical transmission path. In practice, sincetransmission is possible up to a certain distance without 3R relay, a 3Rrepeater 1002 is not necessarily provided in every optical node device1001. However, since the distance over which transmission is possiblewithout 3R relay differs depending on the performance of optical devicescontained in the optical node device, the material of the optical fiberbetween the optical node devices, and the wavelengths used, the distancecannot be determined uniformly, and there is no efficient method ofobtaining the distance over which transmission is possible without 3Rrelay over a whole optical network. Conventionally, as shown in FIG. 87,a 3R repeater 1002 is inserted into each stage so that deterioration ofan optical signal can be compensated regardless of the route throughwhich a path is established (for example, refer to non-patent documents1, 2 and 3).

Non-patent document 1: Eiji Oki, Daisaku Shimazaki, Kohei Shiomoto,Nobaki Matsuura, Wataru Imajuku, and Naoaki Yamanaka, “PerformanceEvaluation of Distributed-Controlled Dynamic Wavelength-Conversion GMPLSNetworks”, Technical report of IEICE, The Institute of Electronics,Information and Communication Engineers, February 2002, pp. 5-10.

Non-patent document 2: Ken-ichi Sato, Naoaki Yamanaka, YoshihiroTakigawa, Masafumi Koga, Satoru Okamoto, Kohei Shiomoto, Eiji Oki, andWataru Imajuku, “GMPLS-Based Photonic Multilayer Router (Hikari Router)Architecture: An Overview of Traffic Engineering and SignalingTechnology”, IEEE Communications Magazine, March 2002, pp. 96-101.

Non-patent document 3: Eiji Oki, Daisaku Shimazaki, Kohei Shiomoto,Nobuaki Matsuura, Wataru Imajuku, and Naoaki Yamanaka, “Performance ofDistributed-Controlled Dynamic Wavelength-Conversion GMPLS Networks”,First International Conference on Optical Communications and Networks2002, Nov. 11-14, 2002, Shangri-La Hotel, Singapore.

3R repeaters are expensive, so if the use of 3R repeaters is avoided asmuch as possible, optical networks can be realized extremelyeconomically. However, conventionally, there is no effective method ofobtaining the distance over which transmission is possible without 3Rrelay over a whole optical network. Hence it is not possible todetermine the places where 3R repeaters do not need to be provided.

Furthermore, conventionally, in each optical node device, 3R relays areprovided in all optical paths passing through the concerned optical nodedevice. Therefore, 3R repeaters are needed to provide 3R relaycapability in a large number of optical paths at the same time, and itis difficult to achieve low cost.

DISCLOSURE OF INVENTION

The present invention is made under such a background, with an object ofproviding an optical node device and an optical network that can usenetwork resources effectively using the minimum number of, or minimumcapability of, 3R repeaters necessary, and configure economical opticalnetworks.

In the present invention, by using 3R sections, being the sections inwhich data transmission is possible without 3R relay, efficiently, orgenerating 3R section information efficiently, it is possible toeliminate the waste of providing 3R repeaters in places that do notrequire 3R relay, achieve effective usage of network resources, andreduce the cost of optical networks. Furthermore, by identifying theplaces that require 3R relay, it is possible to extract an optical paththat actually requires 3R relay in an optical node device from among aplurality of optical paths that pass optical node devices having 3Rrepeaters to provide 3R relay only on this optical path. Hence it ispossible to reduce the capability of the 3R repeaters. Consequently,network resources can be used effectively, and thus it is possible toreduce the cost of the optical network.

Here, in the following description, a preset section in which datatransmission is possible without 3R relay is defined as a 3R section, anoptical node device at a start point of the 3R section is defined as a3R source node, an optical node device at an end point of the 3R sectionis defined as a 3R destination node, an optical node device, being asource of a setting request for an optical path, is defined as a sourcenode, an optical node device at an end point of the optical path isdefined as a destination node, and when the optical path isbi-directional, an optical path directed away from the source nodetoward the destination node is defined as a downstream optical path, andan optical path directed away from the destination node toward thesource node is defined as an upstream optical path.

That is, a first aspect of the present invention is an optical nodedevice that switches an optical signal, the optical node devicecomprising: a storing unit which stores 3R section informationcorresponding to topology information of an optical network to which theoptical node device itself belongs; and a determining unit whichdetermines autonomously whether the optical node device itself is anoptical node device that implements 3R relay when setting an opticalpath passing through the optical node device itself, with reference tothe 3R section information stored in the storing unit which stores the3R section information.

As described above, by storing 3R section information in each opticalnode device, when an optical path is established in itself, if thesource node of the optical path is identified, it is possible todetermine autonomously whether or not itself implements 3R relay of anoptical signal transmitted through the optical path.

Alternatively, an optical node device of the present invention may beprovided with: a storing unit which stores 3R section informationcorresponding to topology information of an optical network to which theoptical node device itself belongs; an identifying unit which identifiesanother optical node device which implements 3R relay among otheroptical node devices through which an optical path from the optical nodedevice itself to the destination node passes with reference to the 3Rsection information stored in the storing unit, when the optical nodedevice itself is the source node; and a unit which requests 3R relay beimplemented in the other optical node device identified by theidentifying unit, when setting an optical path in which the optical nodedevice itself is the source node.

In this manner, since the optical node device other than the source nodedoes not need to determine whether 3R relay is implemented or not, it ispossible to reduce the processing load accordingly. For example, in thecase where a large number of optical paths passes through an opticalnode device and the processing load becomes enormous due to determiningwhether 3R relay is implemented or not for every optical path, it ispossible to reduce the processing load by identifying, from amongst theother optical node devices through which the optical paths pass on theirway to their destination nodes, only the other optical node devices thatimplement 3R relay in optical paths whose source nodes are the presentoptical node device. Furthermore, in this case, only the optical nodedevice corresponding to the source node must store 3R sectioninformation, so it is possible to use information storage resourceseffectively.

Alternatively, an optical node device of the present invention may beprovided with: a storing unit which stores 3R section informationcorresponding to topology information of an optical network to which theoptical node device itself belongs when the optical node device itselfis an optical node device through which an optical path between thesource node and the destination node passes; and a determining unitwhich determines autonomously whether the optical node device itself isan optical node device that implements 3R relay in the optical path,based on the 3R section information stored in the storing unit.

In this manner, since each optical node device stores 3R sectioninformation only when an optical path passes through each optical nodedevice itself, it is possible to use the information storage resourceseffectively.

Furthermore, when the optical path is a bi-directional optical path, thedetermining unit or the identifying unit is preferably provided with aunit which decides which optical node device implements 3R relay in boththe downstream optical path and the upstream optical path.

In this manner, at the time that a bi-directional path setting issignaled, it is possible to decide which optical node device implements3R relay in both the upstream and downstream directions, and immediatelyafter signaling completion, optical signals can be transmitted. Thus itis possible to set optical paths promptly.

Moreover, when one optical node device is a 3R source node of any one ofa plurality of different 3R sections overlapping on an optical path thatpasses through the one optical node device, and the one optical nodedevice is not a 3R source node or 3R destination node of other 3Rsections, the determining unit or the identifying unit is preferablyprovided with: a comparing unit which compares the number of 3R relayimplementations for both the case where the one optical node devicefunctions as a 3R source node and where the one optical node device doesnot function as a 3R source node, with reference to the 3R sectioninformation related to an optical path from the one optical node deviceto the destination node; and a unit which, when the number of 3Rimplementations in the case where the one optical node device functionsas a 3R source node is less than the number of 3R implementations in thecase where the one optical node device does not function as a 3R sourcenode, decides that the one optical node device is an optical node devicethat implements 3R relay based on a comparison result from the comparingunit.

In this manner, since an optical signal can be transmitted by theminimum number of 3R relay operations possible, it is possible to usenetwork resources effectively using the minimum number of, or minimumcapability of, 3R repeaters necessary, and configure economical opticalnetworks.

Furthermore, when one optical node device is an optical node devicecorresponding to a 3R destination node, and is not a destination node,the determining unit or the identifying unit is preferably provided witha unit which decides that the one optical node device is an optical nodedevice that implements 3R relay by using the one optical node device asa 3R source node, and a next hop optical node device as a 3R destinationnode.

In this manner, even in the case where one optical node device is a 3Rdestination node, and this one optical node device does not store 3Rsection information ahead of itself, it is possible to realize 3R relaytransmission without delay.

Moreover, when one optical node device does not belong to any one of 3Rsections having a 3R source node on an optical path that passes throughthe one optical node device, the determining unit or the identifyingunit is preferably provided with a unit which decides that the oneoptical node device is an optical node device that implements 3R relayby using the one optical node device as a 3R source node, and a next hopoptical node device of the one optical node device as a 3R destinationnode.

Furthermore, preferably there is provided a unit which, when one opticalnode device is a 3R source node in an upstream optical path, and is nota destination node, and the one optical node device is not a 3Rdestination node in the upstream optical path, transmits a message inorder to transmit information to a previous hop optical node device inthe upstream optical path that the previous hop optical node device is a3R source node which uses the one optical node device as a 3Rdestination node, wherein the determining unit or the identifying unitis provided with a unit which decides that the optical node deviceitself is a 3R source node in the upstream optical path with an opticalnode device which has sent the message as a 3R destination node when theoptical node device itself receives the message in the upstream opticalpath.

In this manner, even if the optical node device does not correspond toany one of the pieces of existing 3R section information, it is possiblefor this optical node device to implement 3R relay without delay.Accordingly, 3R section information for all of the sections of anoptical network does not need to be stored, and 3R section informationmust only be stored for key places. Thus it is possible to store 3Rsection information efficiently.

Alternatively, the optical node device of the present invention may alsobe provided with: a storing unit which stores information of a 3Rsection in which the optical node device itself is a 3R source node; anda unit which, when the optical node device itself is not a destinationnode on receiving a message, contained in a setting request for anoptical path, indicating that the optical node device itself is a 3Rdestination node, refers to the storing unit, and when the optical nodedevice itself is a 3R source node in the optical path, determines thatthe optical node device itself is an optical node device that implements3R relay, and transmits a message to an optical node device,corresponding to a 3R destination node of a 3R section in an opticalpath in which the optical node device itself is a 3R source node, inorder to transmit that the optical node device corresponding to the 3Rdestination node is a 3R destination node.

In this manner, it is not necessary to store 3R section information notrelated to itself, and thus it is possible to use information storageresources effectively.

Moreover, it is preferable to provide a unit which, when the opticalnode device itself is not a destination node on receiving the message,contained in the setting request for the optical path, indicating thatthe optical node device itself is the 3R destination node, refers to thestoring unit, and when the optical node device itself is not a 3R sourcenode in the optical path, determines that the optical node device itselfis an optical node device that implements 3R relay as a 3R source nodeusing a next hop optical node device as a 3R destination node, andtransmits a message to the next hop optical node device in order totransmit that the next hop optical node device is a 3R destination node.

In this manner, even if the 3R source node only stores 3R sectioninformation up to the 3R destination node related to itself, it ispossible to realize 3R relay transmission in the 3R destination node andthe nodes ahead of the 3R destination node without delay.

In this case, since information of a 3R section in which itself is a 3Rsource node, and 3R section information other than this is not stored,it is determined whether itself is required to function as a 3R sourcenode or a 3R destination node by a message contained in the optical pathsetting request.

For example, when an optical path setting request reaches an opticalnode device, being a 3R source node of a 3R section in an optical path,there is also a possibility that a 3R section other than the 3R sectionthat the optical node device stores is used in an optical path set bythe optical path setting request. However, it is difficult to determinethis from the 3R section information that the optical node devicecontains. Accordingly, the optical node device determines whether itselfneeds to function as a 3R source node or a 3R destination node.

Alternatively, the optical node device of the present invention may alsobe provided with: a storing unit which stores information of a 3Rsection in which the optical node device itself is a 3R source node anda 3R destination node; a unit which, when the optical node device itselfis not a destination node on receiving a message, contained in anoptical path setting request, indicating that the optical node deviceitself is a 3R destination node in the downstream optical path, refersto the storing unit, and when the optical node device itself is a 3Rsource node in the downstream optical path, determines that the opticalnode device itself is an optical node device that implements 3R relay,and transmits a message to an optical node device corresponding to a 3Rdestination node of a 3R section in the downstream optical path in whichthe optical node device itself is a 3R source node, in order to transmitthat the optical node device corresponding to the 3R destination node isa 3R destination node; and a unit which determines that the optical nodedevice itself is an optical node device that implements 3R relay in theupstream optical path on receiving a message, contained in an opticalpath setting request, indicating that the optical node device itself isa 3R source node in the upstream optical path and which, when theoptical node device itself is not a destination node, refers to thestoring unit, and when the optical node device itself is a 3Rdestination node in the upstream optical path, transmits a message to anoptical node device corresponding to a 3R source node in the upstreamoptical path in which the optical node device itself is a 3R destinationnode, in order to transmit that the optical node device corresponding tothe 3R source node is a 3R source node.

In this manner, it is not necessary to store 3R section informationunrelated to itself, and it is possible to set an optical node devicethat implements 3R relay in a bi-directional optical path while usinginformation storage resources effectively.

Furthermore, it is preferable to provide: a unit which, when the opticalnode device itself is not a destination node on receiving the message,contained in the optical path setting request, indicating that theoptical node device itself is the 3R destination node in the downstreamoptical path, refers to the storing unit, and when the optical nodedevice itself is not a 3R source node in the downstream optical path,determines that the optical node device itself is an optical node devicethat implements 3R relay using the optical node device itself as a 3Rsource node and a next hop optical node device in the downstream opticalpath as a 3R destination node, and transmits a message to the next hopoptical node device in order to transmit that the next hop optical nodedevice is a 3R destination node of the optical node device itself; and aunit which determines that the optical node device itself is an opticalnode device that implements 3R relay in the upstream optical path onreceiving the message, contained in the optical path setting request,indicating that the optical node device itself is the 3R source node inthe upstream optical path, and which when the optical node device itselfis not a destination node, refers to the storing unit, and when theoptical node device itself is not a 3R destination node in the upstreamoptical path, transmits a message to a previous hop optical node devicein the upstream optical path, in order to transmit that the previous hopoptical node device is a 3R source node using the optical node deviceitself as a 3R destination node.

In this manner, 3R relay transmission can be realized in a bidirectionaloptical path without delay even in an optical node device that does notstore 3R section information in itself.

Here, in this case, since the 3R section information defining itself asa 3R source node or a 3R destination node is stored, but 3R sectioninformation other than this is not stored, it is determined whetheritself is required to function as a 3R source node or a 3R destinationnode by a message contained in the optical path setting request.

For example, when an optical path setting request reaches an opticalnode device, being a 3R source node or a 3R destination node of a 3Rsection in an optical path, there is also a possibility that a 3Rsection other than the 3R section that the optical node device stores isused in an optical path set by the optical path setting request.However, it is difficult to determine this from the 3R sectioninformation that the optical node device contains. Accordingly, theoptical node device determines whether itself needs to function as a 3Rsource node or a 3R destination node by a message contained in theoptical path setting request.

A second aspect of the present invention is a network control devicethat manages an optical network which is provided with: a plurality ofoptical node devices that switch optical signals; and opticaltransmission paths connecting the plurality of optical node devices.

Here, a network control device of the present invention is provided witha storing unit which stores 3R section information corresponding totopology information of the optical network; and a unit which providesthe 3R section information stored in the storing unit to an optical nodedevice according to a request from the optical node device.

Moreover, the optical node device of the present invention is providedwith an acquiring unit which requests a network control device managingan optical network to which the optical node device itself belongs toprovide 3R section information corresponding to topology information ofthe optical network, and acquires the 3R section information.

Furthermore, it is preferable that the acquiring unit is provided with aunit which selects and stores at least a part of information associatedwith the optical node device itself from the 3R section informationacquired.

That is, in the present invention, there is a case where all opticalnode devices have the same 3R section information, a case where anoptical node device through which an optical path passes stores 3Rsection information, a case where a source node of an optical pathstores 3R section information, and a case where a 3R source node or a 3Rdestination node stores 3R section information associated with itself.

In order to handle each of these cases flexibly, it is convenient tohave a unit which provides each of the optical node devices with the 3Rsection information that each of the optical node devices requestsquickly. For example, using a structure in which a network controldevice is provided, where this network control device provides each ofthe optical node devices with required 3R section information based onrequests from each of the optical node devices, each of the optical nodedevices can obtain the 3R section information itself needs quickly.

For example, in the case where all of the optical node devices storecommon 3R section information, the optical node device according to thepresent invention is provided with: an acquiring unit which requests anetwork control device that manages an optical network to which theoptical node device itself belongs, for 3R section informationcorresponding to topology information of the optical network to whichthe optical node device itself belongs and acquires the 3R sectioninformation; and a unit which stores the 3R section information acquiredby the acquiring unit, and advertises the 3R section information toother optical node devices.

In this manner, some optical node devices request the network controldevice for 3R section information, and acquire it, and these opticalnode devices acquiring 3R section information from the network controldevice advertise it to the other optical node devices. Thus all opticalnode devices can store the common 3R section information. It isdesirable to use such a scheme in the case where network resources canbe used effectively compared with the case where all optical nodedevices request the network control device for 3R section information toacquire it individually.

For example, in the case where an optical node device in the routebetween a source node and a destination node stores 3R sectioninformation, the optical node device of the present invention isprovided with: an acquiring unit which requests a network control devicemanaging an optical network to which the optical node device itselfbelongs for 3R section information corresponding to topology informationof the optical network to which the optical node device itself belongswhen the optical node device itself is a source node, and acquires the3R section information; and a unit which stores the 3R sectioninformation acquired by the acquiring unit, and transmits the 3R sectioninformation to other optical node devices contained in an optical pathup to the destination node when the optical node device itself is usedas the source node.

In this manner, since it is possible for an optical node devicecorresponding to a source node to request the network control device for3R section information, acquire it, and transmit the 3R sectioninformation acquired to the other optical node devices in the route, itis possible to reduce the processing load on the network control deviceand the optical node devices in the route compared with the case wherethe optical node devices in the route request the network control devicefor 3R section information and acquire it individually.

Alternatively, in the case where an optical node device in the routebetween a source node and a destination node stores 3R sectioninformation, it is also possible for the optical node device of thepresent invention to be provided with: an acquiring unit which requestsa network control device managing an optical network to which theoptical node device itself belongs for 3R section informationcorresponding to topology information of the optical network to whichthe optical node device itself belongs when the optical node deviceitself is a source node, and acquires the 3R section information; anadvertising unit which stores the 3R section information acquired by theacquiring unit, and advertises the 3R section information to otheroptical node devices; a determining unit which determines whether anadvertisement by the advertising unit is associated with an optical paththat passes through the optical node device itself; a unit whichdiscards the advertisement when a determination result of thedetermining unit indicates that the advertisement is not associated withthe optical path that passes through the optical node device itself; anda unit which stores contents of the advertisement when the determinationresult of the determining unit indicates that the advertisement isassociated with the optical path which passes through the optical nodedevice itself.

In this manner, an optical node device corresponding to a source noderequests the network control device for 3R section information, acquiresit, and advertises the 3R section information acquired to other opticalnode devices. At this time, an optical node device corresponding to asource node does not need to limit the advertised address to the otheroptical node devices in the route. Thus it is possible to reduce theprocessing load required for such limitation. An optical node devicewhich receives the advertisement, may discard it if the advertisement isnot associated with itself.

Alternatively, the optical node device of the present invention may beprovided with: a storing unit which stores information of the number ofhops H between the optical node device itself and a 3R destination nodein a 3R section to which the optical node device itself belongs; and adetermining unit which determines autonomously whether the optical nodedevice itself implements 3R relay of an optical signal transmitted froma 3R source node in the 3R section to which the optical node deviceitself belongs, wherein the determining unit determines that 3R relay isimplemented, if T>TH_T, and H<TH_H, where T is the number of 3R trunksthat the optical node device itself has, TH_T is a threshold value ofthe number of vacant 3R trunks, and TH_H is a threshold value of thenumber of hops up to the 3R destination node.

That is, in the case where an optical node device is not a 3Rdestination node, but there is a 3R destination node only a few hopsahead, and its 3R trunk has additional processing capability available,it is possible for itself to reduce the 3R relay load of the opticalnode device corresponding to the 3R destination node (that is a 3Rsource node of the next 3R section) by implementing 3R relay instead ofthe 3R destination node.

The threshold values TH_T and TH_H are set appropriately depending onthe 3R relay capability of the optical node device itself or anotheroptical node device corresponding to a 3R destination node. For example,the lower the number of 3R trunks of the 3R source node of the next 3Rsection compared with the number of 3R trunks of the optical node deviceitself, the higher the degree of necessity for the optical node deviceitself to help the 3R relay of the 3R source node of the next 3Rsection. Therefore, it is preferable to set the TH_T low, and for theoptical node device itself to implement 3R relay so as to help the 3Rrelay of the 3R source node of the next 3R section if there is even alittle spare capacity in the 3R trunk of the optical node device itself.However, in the case where the number of hops to the 3R source node ofthe next 3R section is high, even if there is some margin in the numberof 3R trunks of the optical node device itself, if the optical nodedevice itself implements 3R relay instead of the 3R source node of thenext 3R section, there is a possibility that the number of 3R operationsup to a destination node increases. Therefore, it is preferable thatTH_H is low.

In this manner, TH_T and TH_H are set appropriately with considerationof the number of hops of the whole 3R section and the 3R destinationnode, that is, the number of 3R trunks of a 3R source node of the next3R section.

A third aspect of the present invention is an optical network that isprovided with an optical node device of the present invention or anetwork control device of the present invention.

A fourth aspect of the present invention is a decision method of a 3Rrelay implementation node in an optical node device that switches anoptical signal, the method comprising the steps of: when one opticalnode device is a 3R source node of any one of a plurality of different3R sections overlapping on an optical path that passes through the oneoptical node device, and the one optical node device does not correspondto a 3R source node or 3R destination node of other 3R sections,comparing the number of 3R implementations for both the case where theone optical node device functions as a 3R source node and where the oneoptical node device does not function as a 3R source node, withreference to 3R section information related to an optical path from theone optical node device up to the destination node, and deciding thatthe one optical node device is an optical node device that implements 3Rrelay, when the number of 3R implementations is less in the case wherethe one optical node device functions as a 3R source node than in thecase where the one optical node device does not function as a 3R sourcenode, based on a comparison result.

Alternatively, a decision method of a 3R relay implementation node ofthe present invention decides that when one optical node device is anoptical node device corresponding to a 3R destination node, and is not adestination node, the one optical node device is an optical node devicethat implements 3R relay using the one optical node device as a 3Rsource node, and a next hop optical node device as a 3R destinationnode.

Alternatively, a decision method of a 3R relay implementation node ofthe present invention decides that when one optical node device does notbelong to any one of 3R sections having a 3R source node in an opticalpath which passes through the one optical node device, the one opticalnode device is an optical node device that implements 3R relay using theone optical node device as a 3R source node, and a next hop optical nodedevice of the one optical node device as a 3R destination node.

Alternatively, a decision method of a 3R relay implementation node ofthe present invention, when one optical node device is a 3R source node,but not a destination node in the upstream optical path, and the oneoptical node device is not a 3R destination node in the upstream opticalpath, sends a message to a previous hop optical node device in theupstream optical path in order to transmit information that the previoushop optical node device is a 3R source node using the one optical nodedevice as a 3R destination node; and the optical node device receivingthe message in the upstream optical path decides that the optical nodedevice itself is a 3R source node in the upstream optical path using anoptical node device, being a sender of the message, as a 3R destinationnode.

Alternatively, in a decision method of a 3R relay implementation node ofthe present invention, an optical node device corresponding to a 3Rsource node stores 3R section information related to the optical nodedevice itself, referring to the 3R section information when the opticalnode device corresponding to a 3R source node is not a destination nodeon receiving a message, contained in a setting request for an opticalpath, indicating that the optical node device corresponding to a 3Rsource node is a 3R destination node, determining that the optical nodedevice itself is an optical node device that implements 3R relay whenthe optical node device itself is a 3R source node in the optical path,and sending a message to an optical node device corresponding to a 3Rdestination node of a 3R section in an optical path in which the opticalnode device itself is a 3R source node in order to transmit that theoptical node device corresponding to the 3R destination node is a 3Rdestination node.

Furthermore, it is preferable to refer to the 3R section informationwhen the optical node device itself is not a destination node onreceiving the message, contained in the setting request for the opticalpath, that the optical node device itself is the 3R destination node;determine that the optical node device itself is an optical node devicethat implements 3R relay as a 3R source node using a next hop opticalnode device as a 3R destination node when the optical node device itselfis not a 3R source node in the optical path; and transmit a message tothe next hop optical node device in order to transmit that the next hopoptical node device is a 3R destination node.

Alternatively, a decision method of a 3R relay implementation node ofthe present invention is provided with the steps of: storing informationof a 3R section in which an optical node device is a 3R source node anda 3R destination node, and when the optical node device itself is not adestination node on receiving a message, contained in a setting requestfor an optical path, indicating that the optical node device itself is a3R destination node in the downstream optical path, referring to theinformation of the 3R section, and when the optical node device itselfis a 3R source node in the downstream optical path, determining that theoptical node device itself is an optical node device that implements 3Rrelay, and transmitting a message to an optical node devicecorresponding to a 3R destination node of a 3R section in the downstreamoptical path in which the optical node device itself is a 3R sourcenode, in order to transmit that the optical node device corresponding tothe 3R destination node is a 3R destination node, and determining thatthe optical node device itself is an optical node device that implements3R relay in the upstream optical path on receiving a message, containedin a setting request for an optical path, indicating that the opticalnode device itself is a 3R source node in the upstream optical path, andwhen the optical node device itself is not a destination node, referringto the information of the 3R section, and when the optical node deviceitself is a 3R destination node in the upstream optical path,transmitting a message to an optical node device corresponding to a 3Rsource node in the upstream optical path in which the optical nodedevice itself is a 3R destination node, in order to transmit that theoptical node device corresponding to the 3R source node is a 3R sourcenode.

Moreover, it is preferable that the optical node device itself refers tothe information of the 3R section when the optical node device itself isnot a destination node on receiving the message, contained in thesetting request for the optical path, indicating that the optical nodedevice itself is a 3R destination node in the downstream optical path,and when the optical node device itself is not a 3R source node in thedownstream optical path, determines that the optical node device itselfis an optical node device that implements 3R relay using the opticalnode device itself as a 3R source node by using a next hop optical nodedevice in the downstream optical path as a 3R destination node, andtransmits a message to the next hop optical node device to transmit thatthe next hop optical node device is a 3R destination node of the opticalnode device itself, and determines that the optical node device itselfis an optical node device that implements 3R relay in the upstreamoptical path on receiving the message, contained in the setting requestfor the optical path, indicating that the optical node device itself isa 3R source node in the upstream optical path, and when the optical nodedevice itself is not a destination node, refers to the 3R sectioninformation, and when the optical node device itself is not a 3Rdestination node in the upstream optical path, transmits a message to aprevious hop optical node device in the upstream optical path, totransmit that the previous hop optical node device is a 3R source nodeusing the optical node device itself as a 3R destination node.

Alternatively, in a decision method of a 3R relay implementation node ofthe present invention is further provided with the step of: decidingthat one optical node device is an optical node device that implements3R relay, if T>TH_T and H<TH_H, where H is the number of hops betweenthe one optical node device and a 3R destination node in a 3R section towhich the one optical node device belongs, T is the number of 3R trunkswith which the one optical node device is provided, TH_T is a thresholdvalue of the number of vacant 3R trunks, and TH_H is a threshold valueof the number of hops up to the 3R destination node.

A fifth aspect of the present invention is an optical node devicecomprising a switching unit which switches an optical signal, whereinthe setting request for the optical path contains labels for specifyingwavelengths to be used in order from the source node at the time ofswitching from the source node to the destination node, and the labelsare deleted one by one each time a wavelength is set, and the switchingunit is provided with a wavelength conversion unit or a 3R relay unit,and the optical node device further comprises: a unit which storesinformation of the number of hops H between the optical node deviceitself and a 3R destination node of a 3R section to which the opticalnode device itself belongs; and a determining unit which determinesautonomously whether the optical node device itself implements 3R relayof an optical signal transmitted from a 3R source node in the 3R sectionto which the optical node device itself belongs, and the determiningunit determines that 3R relay is implemented if T>TH_T and (H<TH_H andL<TH_L) or T>TH_T and (H<TH_H or L<TH_L), where T is the number oftrunks provided in the wavelength conversion unit or the 3R relay unit,TH_T is a threshold value of the number of vacant trunks, TH_H is athreshold value of the number of hops up to the 3R destination node, Lis the number of remaining labels, and TH_L is a threshold value of thenumber of the remaining labels.

In addition, it is preferable to provide a unit which determines thatthe optical node device itself does not implement 3R relay regardless ofa result determined by the determining unit when the optical node deviceitself belongs to a 3R section in which a 3R destination node is thedestination node.

Furthermore, in an optical node device of the present invention, whenthe optical path is bi-directional, an optical path directed away fromthe source node toward the destination node is defined as a downstreamoptical path, and an optical path directed away from the destinationnode toward the source node is defined as an upstream optical path, andthe setting request for the optical path contains labels for specifyingwavelengths to be used in order from the source node at the time ofswitching from the source node to the destination node, and the labelsare deleted one by one each time a wavelength is set, and the switchingunit is provided with a wavelength conversion unit or a 3R relay unit,and the optical node device further comprises: a unit which storesinformation of the number of hops H between the optical node deviceitself and a 3R destination node of a 3R section to which the opticalnode device itself belongs in the upstream optical path; and adetermining unit which determines autonomously whether the optical nodedevice itself implements 3R relay of an optical signal transmitted froma 3R source node in the 3R section to which the optical node deviceitself belongs in the upstream optical path, and the determining unitdetermines that 3R relay is implemented if T>TH_T and (H<TH_H andL>TH_L) or T>TH_T and (H<TH_H or L>TH_L), where T is the number oftrunks provided in the wavelength conversion unit or the 3R relay unit,TH_T is a threshold value of the number of vacant trunks, TH_H is athreshold value of the number of hops up to the 3R destination node, Lis the number of remaining labels, and TH_L is a threshold value of thenumber of the remaining labels.

It is preferable to provide a unit which determines that the opticalnode device itself does not implement 3R relay regardless of a resultdetermined by the determining unit when the optical node device itselfbelongs to a 3R section in which a 3R destination node is thedestination node.

A sixth aspect of the present invention is an optical networkconstructed using an optical node device of the present invention.

A seventh aspect of the present invention is a decision method of a 3Rrelay implementation node in an optical node device that switches anoptical signal, the method comprising the steps of: deleting labels,contained in the setting request for the optical path, for specifyingwavelengths to be used in order from the source node at the time ofswitching from the source node to the destination node, one by one eachtime a wavelength is used; storing information of the number of hops Hbetween the optical node device and a 3R destination node of a 3Rsection to which the optical node device belongs; and when determiningautonomously whether the optical node device implements 3R relay of anoptical signal transmitted from a 3R source node in the 3R section towhich the optical node device belongs, determining that 3R relay isimplemented if T>TH_T and (H<TH_H and L<TH_L) or T>TH_T and (H<TH_H orL<TH_L), where T is the number of trunks having a function to performwavelength conversion or 3R relay, TH_T is a threshold value of thenumber of vacant trunks, TH_H is a threshold value of the number of hopsup to the 3R destination node, L is the number of remaining labels, andTH_L is a threshold value of the number of the remaining labels.

Here, when the optical node device itself belongs to a 3R section inwhich a 3R destination node is the destination node, it is preferable todetermine that the optical node device itself does not implement 3Rrelay regardless of a determination result.

Moreover, when the optical path is bi-directional, a decision method ofa 3R relay implementation node of the present invention is provided withthe steps of: defining an optical path directed away from the sourcenode toward the destination node as a downstream optical path, and anoptical path directed away from the destination node toward the sourcenode as an upstream optical path; deleting labels, contained in thesetting request for the optical path, for specifying wavelengths to beused in order from the source node at the time of switching from thesource node to the destination node, one by one each time a wavelengthis set; storing information of the number of hops H between the opticalnode device itself and a 3R destination node of a 3R section to whichthe optical node device itself belongs in the upstream optical path; andwhen determining autonomously whether the optical node device itselfimplements 3R relay of an optical signal transmitted from a 3R sourcenode in the 3R section to which the optical node device itself belongsin the upstream optical path, determining that 3R relay is implementedif T>TH_T and (H<TH_H and L>TH_L) or T>TH_T and (H<TH_H or L>TH_L),where T is the number of trunks having a function to perform wavelengthconversion or 3R relay, TH_T is a threshold value of the number ofvacant trunks, TH_H is a threshold value of the number of hops up to the3R destination node, L is the number of remaining labels, and TH_L is athreshold value of the number of the remaining labels.

When the optical node device itself belongs to a 3R section in which a3R destination node is the source node, it is preferable to determinethat the optical node device itself does not implement 3R relayregardless of a determination result.

That is, in the case where an optical node device is not a 3Rdestination node, but there is a 3R destination node only a few hopsahead, and its 3R trunk has additional processing capability available,it is possible for itself to reduce the 3R relay load of the opticalnode device corresponding to the 3R destination node (that is the 3Rsource node of the next 3R section) by implementing the 3R relay insteadof the 3R destination node.

Furthermore, for 3R relay, not only may a specialized 3R repeater for 3Rrelay be used, but a wavelength converter that converts an opticalsignal into an electric signal momentarily, and then converts it into anoptical signal again, may also be used. In this case, an optical pathsetting request contains labels for specifying the wavelengths to beused in order from the source node at the time of switching from asource node to a destination node, and since one label is deleted eachtime one wavelength is used, it is possible to estimate the distance tothe destination node by finding out the number of remaining labels.Therefore, the number of remaining labels is also utilized in thepresent invention.

That is, since the optical node device before a 3R destination nodetakes on the 3R destination node's role to implement 3R relay, theoriginal 3R section may be shortened. Accordingly, if such substitutionis performed out of order, there is a possibility of increasing thenumber of 3R relay operations between a source node and a destinationnode, which is not desirable. Therefore, the present invention addresses3R relay capability, the number of hops to a 3R destination node, andthe number of remaining labels, sets threshold values to them to ensureorder, and prevents an increase in the number of 3R relay operationsfrom the source node to the destination node due to the substitution.

One of the determination rules used at this time is T>TH_T and (H<TH_Hand L<TH_L). That is, in an optical node device in which there issufficient additional 3R relay capability available, the number of hopsto a 3R destination node, and the distance to a destination node, areboth monitored, and when both are below the threshold values, theaforementioned substitution is performed.

Another is T>TH_T and (H<TH_H or L<TH_L). That is, similarly to theprevious, in an optical node device in which there is sufficientadditional 3R relay capability available, the number of hops to a 3Rdestination node, and the distance to a destination node, are bothmonitored. However, even if the distance to the destination node isgreat, if the number of hops to the 3R destination node is low,substitution is performed.

When the two are compared, the former performs substitution only from aposition near to both the 3R destination node and the destination node.Accordingly, the substitution is performed from the point of time thatthe destination node gets close. If the number of hops to the 3Rdestination node is below the threshold value, the latter performssubstitution even if the distance to the destination node is great.Therefore, a greater number of optical node devices can be objects toperform substitution in the latter than in the former.

In the former, since the substitution is performed from the point oftime that the destination node gets close, there is an advantage in thatthe possibility of an increase in the number of 3R operations from thesource node to the destination node is lower than the latter.Furthermore, in the latter, since the optical node device that performssubstitution can be positioned in numerous places in the optical path,there is an advantage in that substitution can be performed efficiently.Since each has different advantages, it is desirable to select theformer or the latter appropriately according to the situation of anoptical network.

Moreover, when itself belongs to a 3R section in which the destinationnode is a 3R destination node, it is preferable to determine that itselfdoes not implement 3R relay. That is, the optical node devicecorresponding to the destination node is an optical node device thatdoes not need to implement 3R relay. Therefore, it is not necessary toconsider substitution for such an optical node device that is notrequired to implement 3R relay.

Furthermore, in the case where an optical path is a bi-directional path,in the upstream optical path, the optical node device that implements 3Rrelay is arranged with a 3R destination node close to a source node, anda 3R source node close to a destination node. Accordingly, the directionof the inequality symbol between the numbers of remaining labels and thethreshold value is reversed compared with the case of a downstreamoptical path. When establishing a physical bi-directional optical path,an optical node device is used that implements 3R relay in both thedownstream and upstream optical paths at the same time.

In this case, when itself belongs to a 3R section in which the sourcenode is a 3R destination node, it is preferable to determine that itselfdoes not implement 3R relay. That is, the optical node devicecorresponding to the source node is an optical node device that does notneed to implement 3R relay in the upstream optical path. Therefore, itis not necessary to consider substitution for such an optical nodedevice that is not required to implement 3R relay.

An eighth aspect of the present invention is an optical node device thatswitches an optical signal, the optical node device comprising: adetecting unit which detects deterioration in the state of an opticalsignal that reaches the optical node device itself; a transmitting unitwhich, when a detection result from the detecting unit indicates signaldeterioration, transmits a 3R relay request to an adjacent optical nodedevice corresponding to one hop before the optical node device itself;and a unit which, when the optical node device itself receives a 3Rrelay request from the transmitting unit of a next hop adjacent opticalnode device, implements 3R relay of an optical signal that reaches theoptical node device itself.

In this manner, by detecting deterioration in the state of an opticalsignal that physically reaches the optical node device itself, itrecognizes the necessity of 3R relay, and requests 3R relayimplementation in an adjacent optical node device corresponding to theprevious hop, and the optical node device which receives this requestactivates a function as an optical node device that implements 3R relay.In this manner, each optical node device can set an appropriate 3Rsection while performing measurement in an optical path setting processor in a switching process of optical signals.

Alternatively, the optical node device of the present invention isprovided with: a detecting unit which detects deterioration in the stateof an optical signal that reaches the optical node device itself; and aunit which, when a detection result from the detecting unit indicatessignal deterioration, implements 3R relay of an optical signal thatreaches the optical node device itself.

In this manner, by detecting deterioration in the state of the opticalsignal that physically reaches the optical node device itself, itrecognizes the necessity of 3R relay, and activates a function as anoptical node device that implements 3R relay. In this manner, eachoptical node device can set an appropriate 3R section while performingmeasurement in an optical path setting process or in a switching processof optical signals.

Alternatively, the optical node device of the present invention is anoptical node device which switches an optical signal and which sets anoptical path for other optical node devices contained in a route fromthe optical node device itself to a destination node which is defined asan optical node device at an end point of the optical path, one hop at atime in order from a next hop adjacent optical node device, the opticalnode device comprising: a transmitting unit which transmits an opticaltest signal each time an optical path is set for the other optical nodedevices contained in the route from the optical node device itself tothe destination node one hop at a time in order from the next hopadjacent optical node device; a receiving unit which, each time theoptical test signal is transmitted to the other optical node devicescontained in the route to the destination node one hop at a time inorder from the next hop adjacent optical node device by the transmittingunit, receives a report of deterioration in the state of the opticaltest signal from another optical node device at the farthest endreceiving the optical test signal; and a unit which, when thedeterioration in the state of the optical test signal based on thereport received by the receiving unit satisfies a predetermineddeterioration condition, requests another optical node devicecorresponding to one hop before the other optical node device at thefarthest end to implement 3R relay, and the other optical node devicethat is requested to implement 3R relay is provided with: a transmissionunit which transmits an optical test signal to the other optical nodedevices contained in a route to the destination node each time anoptical path is set one hop at a time in order from a next hop adjacentoptical node device; a reception unit which, each time the optical testsignal is transmitted to the other optical node devices contained in theroute to the destination node one hop at a time in order from the nexthop adjacent optical node device by the transmission unit, receives areport of deterioration in the state of the optical test signal fromanother optical node device at the farthest end receiving the opticaltest signal; and a unit which, when the deterioration in the state ofthe optical test signal based on the report received by the receptionunit satisfies a predetermined deterioration condition, requests anotheroptical node device corresponding to one hop before the other opticalnode device at the farthest end to implement 3R relay.

In this manner, since it is possible to determine an optical node devicethat implements 3R relay while physically establishing an optical path,3R section information does not need to be generated in advance. Thus itis possible to reduce the processing load required for generating 3Rsection information.

Alternatively, the optical node device of the present invention isprovided with: a unit which stores a value Q, preset for each link basedon optical signal deterioration characteristics in a link between theoptical node device itself and an adjacent node; a unit which, when theoptical node device itself is a source node, transmits an initial valueP of a minuend to a next hop adjacent optical node device; a calculatingunit which, when the optical node device itself receives from a previoushop adjacent optical node device, the initial value P or a minuend valueP′, which has already been reduced from the initial value P, calculates(P−Q) or (P′−Q); a unit which compares a calculated result of thecalculating unit with a threshold value, and when the calculated resultis greater than the threshold value, transmits the calculated result tothe next hop adjacent optical node device, and when the calculatedresult is less than or equal to the threshold value, implements 3R relayof an optical signal that reaches the optical node device itself; and aunit which, when the optical node device itself is not the destinationnode of an optical path to which the value of the minuend istransmitted, transmits the initial value P of the minuend to the nexthop adjacent optical node device using the optical node device itself asa 3R source node.

In this manner, the information stored in each optical node deviceconsists only of the value Q associated with itself, and the initialvalue P to be transmitted to the adjacent optical node device in thecase where itself is a source node, and it is possible to determineautonomously whether or not itself requires 3R relay when establishingan optical path with an extremely small amount of information. Thus itis possible to reduce the processing load required for generation andcollection of 3R section information. Furthermore, when establishing anoptical path, it is not necessary to measure the deterioration in thestate of an optical signal, and thus it is possible to set optical pathspromptly.

Up to this point, the optical node device of the present invention hasbeen described assuming a unidirectional optical path, or a downstreamoptical path of a bi-directional optical path. The following is adescription assuming an upstream optical path of a bi-directionaloptical path.

The optical node device of the present invention is provided with: adetecting unit which detects deterioration in the state of an opticalsignal in the upstream optical path that reaches the optical node deviceitself; a unit which, when a detection result from the detecting unitindicates signal deterioration, transmits a 3R relay implementationrequest to an adjacent optical node device corresponding to a next hopof the optical node device itself; and a unit which, when the opticalnode device itself receives a 3R relay implementation request from aprevious hop adjacent optical node device, implements 3R relay of anoptical signal in the upstream optical path that reaches the opticalnode device itself.

In this manner, by detecting deterioration in the state of an opticalsignal that physically reaches the optical node device itself, itrecognizes the necessity of 3R relay, and requests 3R relayimplementation in the adjacent optical node device corresponding to theprevious hop, and the optical node device itself which receives thisrequest activates a function as an optical node device that implements3R relay. In this manner, each optical node device can set anappropriate 3R section while performing measurement in an optical pathsetting process or in a switching process of optical signals.

Alternatively, the optical node device of the present invention isprovided with a detecting unit which detects deterioration in the stateof an optical signal in the upstream optical path that reaches theoptical node device itself; and a unit which, when a detection resultfrom the detecting unit indicates signal deterioration, implements 3Rrelay of an optical signal in the upstream optical path that reaches theoptical node device itself.

In this manner, by detecting deterioration in the state of the opticalsignal that physically reaches the optical node device itself, itrecognizes the necessity of 3R relay, and activates a function as anoptical node device that implements 3R relay. In this manner, eachoptical node device can set an appropriate 3R section while performingmeasurement in an optical path setting process or in a switching processof optical signals.

Alternatively, the optical node device of the present invention isprovided with: a unit which, when the optical node device itself is asource node, sets an optical path for other optical node devicescontained in a route to the destination node one hop at a time in orderfrom a next hop adjacent optical node device; a unit which, when anoptical path is set in the optical node device itself and when theoptical node device itself is not a source node, transmits an opticaltest signal to the upstream optical path; a unit which, when the opticalnode device itself is a source node, receives the optical test signal,and informs a sender of the optical test signal of a report ofdeterioration in the state of the optical test signal; a unit which,when the optical node device itself is a sender optical node device ofan optical test signal, if the deterioration in the state of the opticaltest signal based on the report satisfies a predetermined deteriorationcondition, implements 3R relay of an optical signal from the upstreamoptical path that reaches the optical node device itself; and a unitwhich, when the optical node device itself is an optical node devicethat implements 3R relay in the upstream optical path, sets an opticalpath for the other optical node devices contained in a route from theoptical node device itself to the destination node one hop at a time inorder from a next hop adjacent optical node device, receives an opticaltest signal, and informs a sender of the optical test signal of a reportof deterioration in the state of the optical test signal.

In this manner, since it is possible to determine an optical node devicethat implements 3R relay while physically establishing an optical path,3R section information does not need to be generated in advance. Thus itis possible to reduce the processing load required for generating 3Rsection information. Here, it is desirable to perform the procedure atthe time of upstream optical path setting at the same time as theprocedure at the time of downstream optical path setting.

Alternatively, the optical node device of the present invention isprovided with: a unit which stores a value q, preset for each link basedon optical signal deterioration characteristics in a link between theoptical node device itself and an adjacent node; a unit which, when theoptical node device itself is a source node, transmits an initial valuep of an augend to a next hop adjacent optical node device; a calculatingunit which, when the optical node device itself receives from a previoushop adjacent optical node device, the initial value p or an augend valuep′, which has already been increased from the initial value p,calculates (p+q) or (p′+q); a unit which compares a calculated result ofthe calculating unit with a threshold value, and when the calculatedresult is less than the threshold value, transmits the calculated resultto a next hop adjacent optical node device, and when the calculatedresult is greater than or equal to the threshold value, implements 3Rrelay of an optical signal that reaches the optical node device itself;and a unit which, when the optical node device itself is not thedestination node of an optical path to which the value of the augend istransmitted, transmits the initial value p of the value of the augend tothe next hop adjacent optical node device using the optical node deviceitself as a 3R destination node in the upstream optical path.

In this manner, the information stored in each optical node deviceconsists only of the value q associated with itself, and the initialvalue p to be transmitted to an adjacent optical node device in the casewhere itself is a source node, and it is possible to determineautonomously whether or not itself requires 3R relay when establishingan optical path with an extremely small amount of information. Thus itis possible to reduce the processing load required for generation andcollection of 3R section information. Furthermore, when establishing anoptical path, it is not necessary to measure the deterioration in thestate of an optical signal, and thus it is possible to establish opticalpaths promptly.

A ninth aspect of the present invention is an optical networkconstructed using the optical node device of the present invention.

A tenth aspect of the present invention is an optical path settingmethod for establishing an optical path for an optical node devicecontained in a path from a source node to a destination node one hop ata time in order from the next hop adjacent optical node device to theoptical node device, being the source node.

Here, an optical path setting method of the present invention performs:a first step of transmitting an optical test signal from an optical nodedevice, being a source node, each time an optical path, is set for theoptical node devices contained in the route to the destination node onehop at a time in order from the next hop adjacent optical node device ofthe optical node device, being the source node; a second step in which,each time the optical test signal is transmitted in the first step tothe optical node devices contained in the route to the destination nodeone hop at a time in order from the next hop adjacent optical nodedevice of the optical node device, being the source node, the opticalnode device, being the source node, receives a report of deteriorationin the state of the optical test signal from an optical node device atthe farthest end that receives the optical test signal; a third step inwhich, when the deterioration in the state of the optical test signalbased on the report received in the second step satisfies apredetermined deterioration condition, the optical node device, beingthe source node, requests an optical node device one hop before theoptical node device at the farthest end to implement 3R relay; a fourthstep in which, each time the optical path is set for the other opticalnode devices contained in the route to the destination node one hop at atime in order from the next hop adjacent optical node device, theoptical node device that is requested to implement 3R relay transmits anoptical test signal; a fifth step in which, each time the optical testsignal is transmitted to the other optical node devices contained in theroute to the destination node, one hop at a time in order from the nexthop adjacent optical node device in the fourth step, the optical nodedevice that is requested to implement 3R relay receives a report ofdeterioration in the state of the optical test signal from the otheroptical node device at the farthest end which receives the optical testsignal; and a sixth step in which, when the deterioration in the stateof the optical test signal based on the report received in the fifthstep satisfies a predetermined deterioration condition, the optical nodedevice that is requested to implement 3R relay requests another opticalnode device one hop before the other optical node device at the farthestend to implement 3R relay.

Alternatively, an eleventh aspect of the present invention is a 3R relayimplementation node setting method in an optical node device thatswitches an optical signal, the method comprising: a step in which eachoptical node device stores a value Q, preset for each link based onoptical signal deterioration characteristics in a link between theoptical node device itself and an adjacent node; a step in which anoptical node device, being a source node, transmits an initial value Pof a minuend to a next hop adjacent optical node device; and a step inwhich each optical node device calculates (P−Q) or (P′−Q) when theoptical node device itself receives from a previous hop adjacent opticalnode device, the initial value P or a minuend value P′, which hasalready been reduced from the initial value P, compares a calculatedresult with a threshold value, and when the calculated result is greaterthan the threshold value, transmits the calculated result to the nexthop adjacent optical node device, and when the calculated result is lessthan or equal to the threshold value, implements 3R relay of an opticalsignal that reaches each optical node device, and when each optical nodedevice is not a destination node of an optical path to which the valueof the minuend is transmitted, transmits the initial value P of theminuend to the next hop adjacent optical node device using each opticalnode device as a 3R source node.

Up to this point, the optical path setting method and 3R relayimplementation node setting method of the present invention have beendescribed assuming a unidirectional optical path, or a downstreamoptical path of a bi-directional optical path. The following is adescription assuming an upstream optical path of a bi-directionaloptical path.

An optical path setting method of the present invention performs: aseventh step in which an optical node device, being a source node, setsan optical path for other optical node devices contained in a route tothe destination node one hop at a time in order from a next hop adjacentoptical node device; an eighth step in which an optical node device thatis not the source node transmits an optical test signal to the upstreamoptical path when an optical path is set in the optical node deviceitself; a ninth step in which the optical node device, being a sourcenode, receives the optical test signal, and gives notification to asender of the optical test signal of a report of deterioration in thestate of the optical test signal; a tenth step in which an optical nodedevice, being the sender of the optical test signal, implements 3R relayof an optical signal in the upstream optical path that reaches theoptical node device itself when the deterioration in the state of theoptical test signal based on the notification satisfies a predetermineddeterioration condition; and an eleventh step in which the optical nodedevice that implements 3R relay in the upstream optical path sets anoptical path for the other optical node devices contained in a routefrom the optical node device itself to the destination node one hop at atime in order from a next hop adjacent optical node device, receives anoptical test signal, and informs a sender of the optical test signal ofreport of deterioration in the state of the optical test signal.

Alternatively, a twelfth aspect of the present invention is a 3R relayimplementation node setting method in an optical node device thatswitches an optical signal, the method comprising: a step in which eachoptical node device stores a value q, preset for each link based onoptical signal deterioration characteristics in a link between theoptical node device itself and an adjacent node; a step in which anoptical node device, being a source node, sends an initial value p of anaugend to a next hop adjacent optical node device; and a step in whicheach optical node device calculates (p+q) or (p′+q) when the opticalnode device itself receives from a previous hop adjacent optical nodedevice, the initial value p or an augend value p′, which has alreadybeen increased from the initial value p, compares a calculated resultwith a threshold value, and when the calculated result is less than thethreshold value, transmits the calculated result to the next hopadjacent optical node device, and when the calculated result is greaterthan or equal to the threshold value, implements 3R relay of an opticalsignal that reaches the optical node device itself, and when eachoptical node device is not the destination node of an optical path towhich the value of the augend is transmitted, transmits the initialvalue p of the augend to the next hop adjacent optical node device usingeach optical node device as a 3R destination node in the upstreamoptical path.

In particular, in the above aspect of the invention, an optical networkcan be easily configured, where at the time of optical path setting, orat the time of switching of optical signals, the respective optical nodedevices can sequentially determine autonomously the necessity of 3Rrelay implementation, and perform 3R relay.

A thirteenth aspect of the present invention is a network control devicethat manages an optical network provided with a plurality of opticalnode devices that switch optical signals, and optical transmission pathsthat connect the plurality of optical node devices, the network controldevice comprising: a topology information storage unit which storestopology information of the optical network; a generating unit whichgenerates in the topology information, estimate information of a 3Rsection in which a specified optical node device is a 3R source nodebased on input information of the number of hops; a changing unit whichchanges part or the whole of the estimate information of the 3R sectionin the topology information generated by the generating unit, based onan input instruction; and a unit which informs information of a 3Rsection in the topology information, changed by the changing unit, tothe optical node device.

In this manner, by inputting the number of estimated hops of a 3Rsection, it is possible to generate approximate 3R section estimateinformation quickly. Although the 3R section estimate information isgenerated approximately in this manner, additional processing such asmeasurement is performed for any link whose physical usage rate is high.Thus it is also possible to increase the reliability of 3R sectioninformation. In this manner, it is possible to generate 3R sectioninformation more quickly than in the case where all of the 3R sectioninformation is generated by measurement.

Furthermore, a fourteenth aspect of the present invention is amaintenance-staff device which supplies input information of the numberof hops to a network control device that manages an optical networkprovided with a plurality of optical node devices that switch opticalsignals, and optical transmission paths that connect the plurality ofoptical node devices, and generates in topology information, estimateinformation of a 3R section in which an optical node device specified isa 3R source node based on the input information of the number of hops,wherein the information of the number of hops is an estimated value ofthe number of hops of a 3R section, the maintenance-staff devicecomprising: a generating unit which generates the estimated value of thenumber of hops; a unit which stores topology information of the opticalnetwork together with optical fiber type information and wavelength bandinformation used in the optical network; and a table in which therelationship between the optical fiber type and wavelength band anddegree of deterioration of an optical signal per unit section is stored,and wherein the generating unit generates the estimated value of thenumber of hops with reference to the optical fiber type information andthe wavelength band information in the topology information, and theoptical fiber type, the wavelength band, and the degree of deteriorationof an optical signal per unit section, stored in the table.

In this manner, it is possible to obtain an estimate of the number ofhops of a 3R section accurately. That is, on a route, there is a largenumber of physical links through the combination of optical fibers onthe route, and wavelengths. The distance over which data transmission ispossible without 3R relay changes due to this variability. For example,the distance over which transmission is possible differs due todifferences of fiber characteristics, such as between normal fiber anddispersion shifted fiber. Therefore, in the case where the number ofestimated hops of a 3R section is obtained, it is possible to obtain anestimated value with less error by obtaining it with reference to theinformation of such optical fiber types and wavelength bands.

Alternatively, a network control device of the present invention isprovided with: a topology information storage unit which stores topologyinformation of the optical network; a generating unit which generates inthe topology information, estimate information of a 3R section in whichan optical node device specified is a 3R source node based on inputinformation of the number of hops; an instructing unit which instructsthe optical node device to set an optical test path in a section of theoptical network corresponding to the estimate information of the 3Rsection in the topology information generated by the generating unit; acollecting unit which collects a measurement result of degree of opticalsignal deterioration due to the optical test path set by the opticalnode device instructed by the instructing unit; a changing unit whichchanges part or all of the estimate information of the 3R section in thetopology information generated by the generating unit based on themeasurement result of the degree of optical signal deteriorationcollected by the collecting unit; and a unit which informs the opticalnode device of information of a 3R section in the topology informationchanged by the changing unit.

In this manner, by inputting an estimate of the number of hops of a 3Rsection, it is possible to generate approximate estimate information ofa 3R section to be measured quickly. By instructing the optical nodedevice to measure based on the 3R section estimate information generatedin this manner, it is possible to generate 3R section information. Inthis manner, since estimated information of a 3R section to be measuredis generated prior to measurement, unnecessary or duplicated measurementcan be avoided. Thus it is possible to generate 3R section informationefficiently.

The present invention is an optical node device which manages an opticalnetwork provided with: a plurality of optical node devices that switchoptical signals; and optical transmission paths that connect theplurality of optical node devices, generating in topology information,estimate information of a 3R section in which an optical node devicespecified is a 3R source node based on input information of the numberof hops, giving an instruction to the optical node device to set theoptical test path in a section of the optical network corresponding tothe estimate information of the 3R section in the generated topologyinformation, collecting the measurement result of the degree of opticalsignal deterioration due to the optical test path set by the opticalnode device by the instruction, changing part or all of the estimateinformation of the 3R section in the topology information generatedbased on the measurement result of the degree of optical signaldeterioration collected, and informs changed information of the 3Rsection in the topology information to the optical node device.

Here, the optical node device of the present invention is provided witha setting unit which sets an optical test path as instructed by thenetwork control device; a measuring unit which measures the degree ofoptical signal deterioration of the optical test path set by the settingunit; and a unit which informs the network control device of ameasurement result by the measuring unit. In this manner, it is possibleto realize automatic collection of 3R section information by a networkcontrol device.

Alternatively, a network control device of the present invention isprovided with: a topology information storage unit which stores topologyinformation of the optical network; a 3R section information storageunit which stores 3R sections set in the optical network, correspondingto the topology information; a collecting unit which collects trafficdemand information in the optical network; and a unit which informs amaintenance-staff of sections in which 3R section information has notbeen generated, among sections in which traffic demand is increased,based on the traffic demand information collected by the collectingunit, with reference to information from the 3R section informationstorage unit.

Alternatively, a network control device of the present invention isprovided with: a topology information storage unit which stores topologyinformation of the optical network; a 3R section information storageunit which stores 3R sections set in the optical network, correspondingto the topology information; a collecting unit which collects trafficdemand information in the optical network; and a unit which generatesnew 3R section information of sections in which 3R section informationhas not been generated, among sections in which traffic demand isincreased, based on the traffic demand information collected by thecollecting unit, with reference to the 3R section information storageunit.

By so doing, it is possible to add new 3R section informationautomatically to the 3R section information collected initially. Inparticular, it is possible to collect 3R section information of sectionsin which traffic demand is increased from the point of time that 3Rsection information was collected initially. In this manner, it ispossible to collect useful 3R section information efficiently.

Alternatively, the optical node device of the present invention isprovided with: a detecting unit which detects deterioration in the stateof an optical signal that reaches the optical node device itself; anotifying unit which, when a detection result from the detecting unitindicates signal deterioration, notifies an adjacent optical node deviceone hop before the optical node device itself that the adjacent opticalnode device is a 3R destination node, and also a 3R source node of anext 3R section; a unit which, when the optical node device itselfreceives notification from the notifying unit of a next hop adjacentoptical node device, recognizes that the optical node device itself is a3R destination node, and also a 3R source node of a next 3R section; andan updating unit which updates information of a 3R section the opticalnode device itself stores based on a recognition result.

In this manner, by detecting the deterioration in the state of theoptical signal that physically reaches the optical node device itself,the necessity of 3R relay is recognized, and the necessity of 3R relayis notified to the adjacent optical node device corresponding to theprevious hop, and on receiving this notification, the optical nodedevice recognizes that itself is a 3R destination node, and also a 3Rsource node of the next 3R section. Therefore, 3R section informationcan be generated based on the notification. In this manner, each opticalnode device can set an appropriate 3R section while performingmeasurement in an optical path setting process or in a switching processof optical signals, and furthermore, can update the 3R sectioninformation.

Alternatively, the optical node device of the present invention isprovided with a detecting unit which detects deterioration in the stateof an optical signal that reaches the optical node device itself; a unitwhich, when a detection result from the detecting unit indicates signaldeterioration, recognizes that the optical node device itself is a 3Rdestination node, and also a 3R source node of a next 3R section; and anupdating unit which updates information of a 3R section the optical nodedevice itself stores based on a recognition result.

In this manner, by detecting the deterioration in the state of theoptical signal that physically reaches the optical node device itself,the necessity of 3R relay is recognized, and it is recognized thatitself is a 3R destination node, and also a 3R source node of the next3R section. In this manner, it is possible to generate 3R sectioninformation based on the detection result. By so doing, each opticalnode device can set an appropriate 3R section while performingmeasurement in an optical path setting process or in a switching processof optical signals, and furthermore, can update 3R section information.

Moreover, it is preferable to provide a unit which advertises theinformation of the 3R section updated by the updating unit to otheroptical node devices; and a unit which receives an advertisement fromthe other optical node devices, and updates the information of the 3Rsection the optical node device itself stores. That is, it is possibleto recognize that itself is a 3R destination node or a 3R source node bythe measurement of an optical signal that reaches itself, but thisrecognition result is a recognition result that can only be seen by theoptical node device itself. Therefore, by advertising this recognitionresult to other optical node devices, it is possible to synchronize the3R section information updated by the updating unit and share it withall the optical node devices, and utilize it effectively.

Alternatively, the optical node device of the present invention is anoptical node device switching an optical signal and comprising: atransmitting unit which transmits an optical test signal each time anoptical path is set for other optical node devices contained in theroute from the optical node device itself to the destination node onehop at a time in order from a next hop adjacent optical node device; areceiving unit which, each time the optical test signal is transmittedto the other optical node devices contained in the route to thedestination node one hop at a time in order from the next hop adjacentoptical node device by the transmitting unit, receives a report ofdeterioration in the state of the optical test signal from anotheroptical node device at the farthest end which receives the optical testsignal; and a unit which, when the deterioration in the state of theoptical test signal based on the report received by the receiving unitsatisfies a predetermined deterioration condition, gives notification toanother optical node device corresponding to one hop before the otheroptical node device at the farthest end that the other optical nodedevice corresponding to one hop before the other optical node device atthe farthest end is a 3R destination node, and also a 3R source node ofa next 3R section, wherein the other optical node device that receivesthe notification is provided with: a transmission unit which transmitsan optical test signal each time an optical path is set for otheroptical node devices contained in a route to the destination node onehop at a time in order from a next hop adjacent optical node device; areception unit which, each time the optical test signal is transmittedto the other optical node devices contained in the route to thedestination node one hop at a time in order from the next hop adjacentoptical node device by the transmission unit, receives a report ofdeterioration in the state of the optical test signal from anotheroptical node device at the farthest end which receives the optical testsignal; and a unit which, when the deterioration in the state of theoptical test signal based on the report received by the reception unitsatisfies a predetermined deterioration condition, informs anotheroptical node device corresponding to one hop before the other opticalnode device at the farthest end that the other optical node devicecorresponding to one hop before the other optical node device at thefarthest end is a 3R destination node, and also a 3R source node of anext 3R section.

In this manner, since it is possible to generate 3R section informationwhile physically establishing an optical path, 3R section informationdoes not need to be generated in advance. Thus it is possible to reducethe processing load required for generating 3R section information.

Alternatively, the optical node device of the present invention isprovided with: a setting unit which sets an optical test path from theoptical node device itself to other optical node devices contained in alink to be measured, being a measurement object of 3R sectioninformation, one hop at a time in order from a next hop adjacent opticalnode device: a transmitting unit which transmits an optical test signaleach time the optical test path is set for the other optical nodedevices contained in the link to be measured one hop at a time in orderfrom the next hop adjacent optical node device by the setting unit; areceiving unit which, each time the optical test signal is transmittedto the other optical node devices contained in the link to be measuredone hop at a time in order from the next hop adjacent optical nodedevice by the transmitting unit, receives a report of deterioration inthe state of the optical test signal from another optical node device atthe farthest end that receives the optical test signal; and arecognizing unit which, when the deterioration in the state of theoptical test signal based on the report received by the receiving unitsatisfies a predetermined deterioration condition, recognizes anotheroptical node device corresponding to one hop before the other opticalnode device at the farthest end as a 3R destination node, and also a 3Rsource node, of a next 3R section.

In this manner, since it is possible to generate 3R section informationby the same procedure as in the case of physical optical path setting,it is possible to generate 3R section information with high accuracybased on measurement.

In this case, it is preferable to provide a unit which stores arecognition result from the recognizing unit. By so doing, it ispossible to store 3R section information when establishing an opticalpath with the optical node device itself being a source node.

Alternatively, by providing a unit which advertises a recognition resultfrom the recognizing unit to other optical node devices; and a unitwhich receives an advertisement from other optical node devices, andstores a recognition result contained in the advertisement together witha recognition result of the optical node itself device, it is possiblefor each optical node device to share 3R section information generatedby itself and others. By so doing, it is possible to store 3R sectioninformation not only in the case where the optical node device itself isa source node, but also in the case where another optical node device isa source node. Hence it is possible to determine whether the opticalnode device itself implements 3R relay or not by itself in the casewhere another optical node device is a source node. Accordingly, it ispossible to reduce the processing load when an optical node device,being a source node, requests the optical node device that implements 3Rrelay to implement 3R relay.

Alternatively, it is also possible to provide a unit which notifies anetwork control device which manages an optical network and stores 3Rsection information in the optical network, of a recognition result fromthe recognizing unit.

In this manner, it is possible for a network control device to store 3Rsection information for the whole optical network. Accordingly, since anoptical node device can request a network control device for 3R sectioninformation as required, and acquire it, it is not necessary to providelarge memory storage such as a database in the optical node device.Furthermore, it is not necessary for each optical node device toadvertise the 3R section information generated by itself to the otheroptical node devices, and must advertise the 3R section information thatitself generates only to the network control device. Thus it is possibleto reduce the processing load required for advertisement.

The network control device in this case is provided with a unit whichreceives information of the 3R destination node or 3R source node fromthe optical node device that configures the optical network, and updatesthe 3R section information stored.

Alternatively, the optical node device of the present invention isprovided with: a unit which stores a value Q, preset for each link basedon optical signal deterioration characteristics in a link between theoptical node device itself and an adjacent node; a unit which, when theoptical node device itself is a source node, transmits an initial valueP of a minuend to a next hop adjacent optical node device; a calculatingunit which, when the optical node device itself receives from a previoushop adjacent optical node device, the initial value P or a minuend valueP′, which has already been reduced from the initial value P, calculates(P−Q) or (P′−Q); a unit which compares a calculated result of thecalculating unit with a threshold value, and when the calculated resultis greater than the threshold value, transmits the calculated result tothe next hop adjacent optical node device, and when the calculatedresult is less than or equal to the threshold value, recognizes that theoptical node device itself is a 3R destination node when an optical nodedevice that transmits the initial value P of the minuend is a 3R sourcenode; and a unit which, when it is recognized that the optical nodedevice itself is a 3R destination node, and the optical node deviceitself is not a destination node of an optical path to which the valueof the minuend is transmitted, transmits the initial value P of theminuend to the next hop adjacent optical node device using the opticalnode device itself as a 3R source node.

In this manner, the information stored in each optical node deviceconsists only of the value Q associated with itself, and the initialvalue P to be transmitted to an adjacent optical node device in the casewhere itself is a source node, so it is possible to generate 3R sectioninformation using an extremely small amount of information. Furthermore,since it is possible to determine autonomously whether or not itselfrequires 3R relay when establishing an optical path, it is possible toreduce the processing load required for advertisement and the like.Furthermore, when establishing an optical path, it is not necessary tomeasure the deterioration in the state of an optical signal. Thus it ispossible to set optical paths promptly.

Up to this point, the optical node device and a network control deviceof the present invention have been described assuming a unidirectionaloptical path, or a downstream optical path of a bi-directional opticalpath. The following is a description assuming an upstream optical pathof a bi-directional optical path.

The optical node device of the present invention is provided with: adetecting unit which detects deterioration in the state of an opticalsignal in the upstream optical path that reaches the optical node deviceitself; a notifying unit which, when a detection result from thedetecting unit indicates signal deterioration, notifies a next hopadjacent optical node device of the optical node device itself, that thenext hop adjacent optical node device is a 3R destination node of theupstream optical path, and also a 3R source node of a next 3R section; aunit which, when the optical node device itself receives notificationfrom the notifying unit of a previous hop adjacent optical node device,recognizes that the optical node device itself is a 3R destination nodeof the upstream optical path, and also a 3R source node of a next 3Rsection; and an updating unit which updates information of a 3R sectionthe optical node device itself stores, based on a recognition result.

Alternatively, the optical node device of the present invention isprovided with: a detecting unit which detects deterioration in the stateof an optical signal in the upstream optical path that reaches theoptical node device itself; a unit which, when a detection result fromthe detecting unit indicates signal deterioration, recognizes that theoptical node device itself is a 3R destination node of the upstreamoptical path, and also a 3R source node of a next 3R section; and anupdating unit which updates information of a 3R section the optical nodedevice itself stores, based on a recognition result.

In this manner, in the case where an optical path is bi-directional,each optical node device can set an appropriate 3R section whileperforming measurement in an optical path setting process or inswitching a process of optical signals, and furthermore can update the3R section information.

Moreover, it is preferable to provide: a unit which advertises theinformation of the 3R section updated by the updating unit to otheroptical node devices; and a unit which receives an advertisement fromthe other optical node devices, and updates the information of the 3Rsection the optical node device itself stores. That is, it is possibleto recognize that itself is a 3R destination node or a 3R source node bythe measurement of an optical signal that reaches itself, but thisrecognition result is a recognition result that can only be seen by theoptical node device itself. Therefore, by advertising this recognitionresult to other optical node devices, it is possible to synchronize the3R section information updated by the updating unit and share it withall the optical node devices, and utilize it effectively

Alternatively, the optical node device of the present invention isprovided with: a unit which, when the optical node device itself is asource node, sets an optical path for other optical node devicescontained in a route to the destination node one hop at a time in orderfrom a next hop adjacent optical node device; a unit which, when theoptical node device itself is not a source node, and when an opticalpath is set in the optical node device itself, transmits an optical testsignal to the upstream optical path; a unit which, when the optical nodedevice itself is a source node, receives the optical test signal, andgive notification to a sender of the optical test signal of a report ofdeterioration in the state of the optical test signal; a unit which,when the optical node device itself is an optical node device being thesender of the optical test signal, and when the deterioration in thestate of the optical test signal based on the notification satisfies apredetermined deterioration condition, recognizes that the optical nodedevice itself is a 3R source node in the upstream optical path, and alsoa 3R destination node of a previous 3R section; and a unit which, whenthe optical node device itself is an optical node device that recognizesthat the optical node device itself is a 3R source node in the upstreamoptical path, and also a 3R destination node of the previous 3R section,sets an optical path for the other optical node devices contained in aroute from the optical node device itself to the destination node onehop at a time in order from the next hop adjacent optical node device,receives the optical test signal, and notifies the sender of the opticaltest signal of the report of the deterioration in the state of theoptical test signal.

In this manner, in the case where an optical path is bi-directional,since it is possible to generate 3R section information while physicallyestablishing an optical path, 3R section information does not need to begenerated in advance. Thus it is possible to reduce the processing loadrequired for generating 3R section information.

Alternatively, the optical node device of the present invention isprovided with: a unit which, when the optical node device itself is asource node, sets an upstream optical test path in other optical nodedevices contained in a link to be measured, being a measurement objectof 3R section information, one hop at a time in order from a next hopadjacent optical node device; a unit which, when the optical node deviceitself is an optical node device in which the upstream optical test pathis set, sends an optical test signal to the upstream optical test path;a unit which, when the optical node device itself is a source node,receives the optical test signal, and notifies a sender of the opticaltest signal of a report of deterioration in the state of the opticaltest signal; a recognizing unit which, when the optical node deviceitself is an optical node device being the sender of the optical testsignal, and when the deterioration in the state of the optical testsignal based on the report satisfies a predetermined deteriorationcondition, recognizes that the optical node device itself is a 3R sourcenode in the upstream optical path, and also a 3R destination node of aprevious 3R section; and a unit which, when the optical node deviceitself is an optical node device that recognizes that the optical nodedevice itself is a 3R source node in the upstream optical path, and alsoa 3R destination node of the previous 3R section, sets an upstreamoptical test path in the other optical node devices contained in a linkto be measured, being a measurement object of 3R section information,one hop at a time in order from the next hop adjacent optical nodedevice, receives the optical test signal, and informs the sender of theoptical test signal of a report of deterioration in the state of theoptical test signal.

In this manner, in the case where an optical path is bi-directional,since it is possible to generate 3R section information by the sameprocedure as in the case of physical optical path setting, it ispossible to generate 3R section information with high accuracy based onmeasurement.

In this case, it is preferable to provide a unit which stores arecognition result from the recognizing unit. By so doing, it ispossible to store 3R section information when establishing an opticalpath with the optical node device itself being a source node.

Alternatively, by providing a unit which advertises a recognition resultfrom the recognizing unit to other optical node devices; and a unitwhich receives an advertisement from other optical node devices, andstores a recognition result contained in the advertisement together witha recognition result of the optical node itself device, it is possiblefor each optical node device to share 3R section information generatedby itself and others. By so doing, it is possible to store 3R sectioninformation not only in the case where the optical node device itself isa source node, but also in the case where another optical node device isa source node. Hence it is possible to determine whether the opticalnode device itself implements 3R relay or not by itself in the casewhere another optical node device is a source node. Accordingly, it ispossible to reduce the processing load when an optical node device,being a source node, requests the optical node device that implements 3Rrelay to implement 3R relay.

Alternatively, it is also possible to provide a unit which notifies anetwork control device which manages an optical network and stores 3Rsection information in the optical network, of a recognition result fromthe recognizing unit.

In this manner, it is possible for a network control device to store 3Rsection information of the whole optical network. Accordingly, since anoptical node device can request a network control device for 3R sectioninformation as required, and acquire it, it is not necessary to providelarge memory storage such as a database in the optical node device.Furthermore, it is not necessary for each optical node device toadvertise the 3R section information generated by itself to the otheroptical node devices, and must notify the 3R section information thatitself generates only to the network control device. Thus it is possibleto reduce the processing load required for advertisement.

The network control device in this case is provided with a unit whichreceives information of the 3R destination node or 3R source node fromthe optical node device that configures the optical network, and updatesthe 3R section information stored.

Alternatively, the optical node device of the present invention isprovided with: a unit which stores a value q, preset for each link basedon optical signal deterioration characteristics in a link between theoptical node device itself and an adjacent node; a unit which, when theoptical node device itself is a source node, transmits an initial valuep of an augend to a next hop adjacent optical node device; a calculatingunit which, when the optical node device itself receives from a previoushop adjacent optical node device, the initial value p or an augend valuep′, which has already been increased from the initial value p,calculates (p+q) or (p′+q); a unit which compares a calculated result ofthe calculating unit with a threshold value, and when the calculatedresult is less than the threshold value, transmits the calculated resultto the next hop adjacent optical node device, and when the calculatedresult is greater than or equal to the threshold value, recognizes thatthe optical node device itself is a 3R source node when an optical nodedevice that transmits the initial value p of the augend is a 3Rdestination node in the upstream optical path; and a unit which, whenthe optical node device itself recognizes that the optical node deviceitself is a 3R source node in the upstream optical path, and is not adestination node of an optical path to which the value of the augend istransmitted, transmits the initial value p of the augend to the next hopadjacent optical node device using the optical node device itself as a3R destination node in the upstream optical path.

In this manner, the information stored in each optical node deviceconsists only of the value q associated with itself, and the initialvalue p to be transmitted to an adjacent optical node device in the casewhere itself is a source node, it is possible to generate the 3R sectioninformation with an extremely small amount of information. Furthermore,since it is possible to determine autonomously whether or not itselfrequires 3R relay when establishing an optical path, it is possible toreduce the processing load required for advertisement. Furthermore, whenestablishing an optical path, it is not necessary to measure thedeterioration in the state of an optical signal, and thus it is possibleto set optical paths promptly.

A fifteenth aspect of the present invention is an optical network thatis provided with an optical node device, a maintenance-staff device, ora network control device, of the present invention.

A sixteenth aspect of the present invention is a method of generating 3Rsection information in a path from a source node to a destination node,which performs: a first step of transmitting an optical test signal froman optical node device being the source node each time an optical path,is set for optical node devices contained in a route to the destinationnode one hop at a time in order from a next hop adjacent optical nodedevice of the optical node device, being the source node; a second stepin which, each time the optical test signal is transmitted in the firststep to the optical node devices contained in the route to thedestination node one hop at a time in order from the next hop adjacentoptical node device of the optical node device, being the source node,the optical node device, being the source node, receives a report ofdeterioration in the state of the optical test signal from an opticalnode device at the farthest end that receives the optical test signal; athird step in which, when the deterioration in the state of the opticaltest signal based on the report received in the second step satisfies apredetermined deterioration condition, the optical node device, beingthe source node, gives notification to an optical node device one hopbefore the optical node device at the farthest end that the optical nodedevice one hop before the optical node device at the farthest end is a3R destination node, and also a 3R source node of a next 3R section; afourth step in which an optical node device which receives thenotification transmits an optical test signal each time an optical pathis set for optical node devices contained in a route to the destinationnode one hop at a time in order from a next hop adjacent optical nodedevice to the optical node device itself; a fifth step in which theoptical node device which receives the notification receives a report ofdeterioration in the state of the optical test signal from the opticalnode device at the farthest end which receives the optical test signal,each time the optical test signal is transmitted in the fourth step tothe optical node devices contained in the route to the destination nodeone hop at a time in order from the next hop adjacent optical nodedevice to the optical node device itself; and a sixth step in which,when the deterioration in the state of the optical test signal based onthe report received in the fifth step satisfies a predetermineddeterioration condition, the optical node device which receives thenotification informs an optical node device one hop before the opticalnode device at the farthest end that the optical node device one hopbefore the optical node device at the farthest end is a 3R destinationnode, and also a 3R source node, of a next 3R section.

Alternatively, a method of generating 3R section information of thepresent invention performs: a seventh step in which an optical nodedevice, being a 3R source node, sets an optical test path to opticalnode devices contained in a link to be measured, being a measurementobject of 3R section information, one hop at a time in order from a nexthop adjacent optical node device; an eighth step of transmitting anoptical test signal, each time the optical test path is set for theoptical node devices contained in the link to be measured one hop at atime in order from the next hop adjacent optical node device of theoptical node device, being the 3R source node, in the seventh step; aninth step in which the optical node device, being the 3R source node,receives a report of deterioration in the state of the optical testsignal from an optical node device at the farthest end which receivesthe optical test signal, each time the optical test signal istransmitted to the optical node devices contained in the link to bemeasured one hop at a time in order from the next hop adjacent opticalnode device of the optical node device, being the 3R source node, in theeighth step; and a tenth step in which, when the deterioration in thestate of the optical test signal based on the report received in theninth step satisfies a predetermined deterioration condition, theoptical node device, being the 3R source node, recognizes an opticalnode device one hop before the optical node device at the farthest endas a 3R destination node.

Alternatively, a method of generating 3R section information of thepresent invention is further provided with: a step in which each opticalnode device stores a value Q, preset for each link based on opticalsignal deterioration characteristics in a link between each optical nodedevice and an adjacent node; a step in which an optical node device,being a source node, transmits an initial value P of a minuend to a nexthop adjacent optical node device; a step in which each optical nodedevice calculates (P−Q) or (P′−Q) when each optical node device receivesfrom a previous hop adjacent optical node device, the initial value P ora value of a minuend P′, which has already been reduced from the initialvalue P, compares a calculated result with a threshold value, and whenthe calculated result is greater than the threshold value, each opticalnode device transmits the calculated result to the next hop adjacentoptical node device, and when the calculated result is less than orequal to the threshold value, each optical node device recognizes thatthe optical node device itself is a 3R destination node when the opticalnode device that has transmitted the initial value P of the minuend is a3R source node, and when each optical node recognizes that the opticalnode device itself is a 3R destination node, and when the optical nodedevice itself is not a destination node of an optical path to which thevalue of the minuend is transmitted, each optical node device transmitsthe initial value P of the minuend to the next hop adjacent optical nodedevice using the optical node device itself as a 3R source node.

Up to this point, the method of generating 3R section informationaccording to the present invention has been described assuming aunidirectional optical path, or a downstream optical path of abi-directional optical path. The following is a description assuming anupstream optical path of a bi-directional optical path.

A method of generating 3R section information of the present inventionperforms: an eleventh step in which an optical node device, being asource node, sets an optical path for other optical node devicescontained in a route to the destination node one hop at a time in orderfrom a next hop adjacent optical node device; a twelfth step in which anoptical node device that is not a source node transmits an optical testsignal to the upstream optical path when an optical path is set in theoptical node device that is not the source node; a thirteenth step inwhich the optical node device, being a source node, receives the opticaltest signal, and informs a sender of the optical test signal of a reportof deterioration in the state of the optical test signal; a fourteenthstep in which, when the deterioration in the state of the optical testsignal based on the report satisfies a predetermined deteriorationcondition, the optical node device being the sender of the optical testsignal, recognizes that the optical node device being the sender of theoptical test signal, is a 3R source node in the upstream optical path,and also a 3R destination node of a previous 3R section; and a fifteenthstep in which the optical node device that recognizes that the opticalnode device itself is a 3R source node in the upstream optical path, andalso a 3R destination node of the previous 3R section, sets an opticalpath for other optical node devices contained in a route from theoptical node device itself to the destination node one hop at a time inorder from a next hop adjacent optical node device, receives the opticaltest signal, and informs a sender of the optical test signal of a reportof deterioration in the state of the optical test signal.

Alternatively, a method of generating 3R section information of thepresent invention performs: a sixteenth step in which an optical nodedevice, being a source node, sets an upstream optical test path in otheroptical node devices contained in a link to be measured, being ameasurement object of 3R section information, one hop at a time in orderfrom a next hop adjacent optical node device; a seventeenth step inwhich an optical node device in which the upstream optical test path isset transmits an optical test signal to the upstream optical test path;an eighteenth step in which the optical node device, being the sourcenode, receives the optical test signal, and notifies a report ofdeterioration in the state of the optical test signal to a sender of theoptical test signal; a nineteenth step in which, when the deteriorationin the state of the optical test signal based on the report satisfies apredetermined deterioration condition, the optical node device being thesender of the optical test signal, recognizes that the optical nodedevice, being the sender of the optical test signal, is a 3R source nodein the upstream optical path, and also a 3R destination node of aprevious 3R section; and a twentieth step, in which the optical nodedevice that recognizes that the optical node device itself is a 3Rsource node in the upstream optical path, and also a 3R destination nodeof the previous 3R section, sets an upstream optical test path for theother optical node devices contained in the link to be measured, being ameasurement object of 3R section information, one hop at a time in orderfrom the next hop adjacent optical node device, receives the opticaltest signal, and informs the sender of the optical test signal of thereport of the deterioration in the state of the optical test signal.

Alternatively, a method of generating 3R section information of thepresent invention is further provided with: a step in which each opticalnode device stores a value q, preset for each link based on opticalsignal deterioration characteristics in a link between each optical nodedevice and an adjacent node; a step in which an optical node device,being a source node, transmits an initial value p of an augend to a nexthop adjacent optical node device; and a step in which each optical nodedevice calculates (p+q) or (p′+q) when each optical node device receivesfrom a previous hop adjacent optical node device, the initial value p ora value of an augend p′, which has already been increased from theinitial value p, compares a calculated result with a threshold value,and when the calculated result is less than the threshold value,transmits the calculated result to the next hop adjacent optical nodedevice, and when the calculated result is greater than or equal to thethreshold value, recognizes that the optical node device itself is a 3Rsource node when the optical node device that has transmitted theinitial value p of the augend is a 3R destination node of the upstreamoptical path, and when each optical node device recognizes that theoptical node device itself is a 3R source node of the upstream opticalpath, and is not a destination node of an optical path to which thevalue of the augend is transmitted, each optical node device transmitsthe initial value p of the augend to the next hop adjacent optical nodedevice using the optical node device itself as a 3R destination node ofthe upstream optical path.

As described above, according to the present invention, it is possibleto realize effective usage of network resources using the minimum numberor minimum capability of 3R repeaters necessary, and to construct aneconomical optical network.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is an explanatory diagram of the denotation of a 3R source node,a 3R destination node, and a 3R section.

FIG. 2 is an explanatory diagram of the character of 3R sections.

FIG. 3 shows an example of 3R section information corresponding totopology information of an optical network.

FIG. 4 is a schematic block diagram of an optical node device accordingto first, third, fifth, sixth, twelfth, and sixteenth embodiments.

FIG. 5 is a diagram showing optical paths and 3R sections set in anoptical network.

FIG. 6 is a block diagram of a 3R relay implementation determining unit.

FIG. 7 is an explanatory diagram of the operation of a 3R implementationsimulating unit.

FIG. 8 shows a signaling procedure when setting an optical path in thefirst embodiment.

FIG. 9 shows optical paths and 3R sections set in an optical network.

FIG. 10 shows a signaling procedure when setting an optical path in thefirst embodiment.

FIG. 11 is a schematic block diagram of an optical node device of asecond embodiment.

FIG. 12 shows a signaling procedure when setting an optical path in thesecond embodiment.

FIG. 13 shows a signaling procedure when setting an optical path in thesecond embodiment.

FIG. 14 shows 3R section information according to third and fourthembodiments.

FIG. 15 shows optical paths and 3R sections set in an optical network.

FIG. 16 shows a signaling procedure when setting an optical path in thethird embodiment.

FIG. 17 shows a signaling procedure when setting an optical path in thefourth embodiment.

FIG. 18 shows optical paths and 3R sections set in an optical network.

FIG. 19 shows a signaling procedure when setting an optical path in thethird embodiment.

FIG. 20 shows a signaling procedure when setting an optical path in thefourth embodiment.

FIG. 21 shows 3R section information in the optical node deviceaccording to the fifth embodiment.

FIG. 22 shows 3R section information in the optical node deviceaccording to the fifth embodiment.

FIG. 23 shows a signaling procedure when setting an optical path in thefifth embodiment.

FIG. 24 shows 3R section information in the optical node deviceaccording to the fifth embodiment.

FIG. 25 shows 3R section information in the optical node deviceaccording to the fifth embodiment.

FIG. 26 shows a signaling procedure when setting an optical path in thefifth embodiment.

FIG. 27 shows 3R section information in the optical node deviceaccording to the sixth embodiment.

FIG. 28 shows 3R section information in the optical node deviceaccording to the sixth embodiment.

FIG. 29 shows 3R section information in the optical node deviceaccording to the sixth embodiment.

FIG. 30 shows 3R section information in the optical node deviceaccording to the sixth embodiment.

FIG. 31 shows a signaling procedure when setting an optical path in thesixth embodiment.

FIG. 32 shows 3R section information in the optical node deviceaccording to the sixth embodiment.

FIG. 33 shows 3R section information in the optical node deviceaccording to the sixth embodiment.

FIG. 34 shows 3R section information in the optical node deviceaccording to the sixth embodiment.

FIG. 35 shows 3R section information in the optical node deviceaccording to the sixth embodiment.

FIG. 36 shows a signaling procedure when setting an optical path in thesixth embodiment.

FIG. 37 is a conceptual diagram showing the relation of a networkcontrol device and optical node devices in seventh and eighthembodiments.

FIG. 38 is a block diagram of the network control device according tothe seventh and eighth embodiments.

FIG. 39 is a schematic block diagram of the optical node deviceaccording to the seventh embodiment.

FIG. 40 is a sequence diagram showing the operation of the seventhembodiment.

FIG. 41 is a schematic block diagram of an optical node device accordingto the eighth embodiment.

FIG. 42 is a sequence diagram showing the operation of the eighthembodiment.

FIG. 43 is a schematic block diagram of an optical node device accordingto a ninth embodiment.

FIG. 44 is a schematic block diagram of an optical node device accordingto a tenth embodiment.

FIG. 45 is a schematic block diagram of an optical node device accordingto an eleventh embodiment.

FIG. 46 is an explanatory diagram of a 3R relay implementation nodedetermination method according to the twelfth embodiment.

FIG. 47 is an explanatory diagram of a 3R relay implementation nodedetermination method according to thirteenth to sixteenth embodiments.

FIG. 48 is an explanatory diagram of the operation of optical nodedevices according to the thirteenth and fourteenth embodiments.

FIG. 49 is an explanatory diagram of the operation of optical nodedevices according to the fifteenth and sixteenth embodiments.

FIG. 50 is an explanatory diagram of the schematic block configurationand the operation of optical node devices according to a seventeenthembodiment.

FIG. 51 is a block diagram of a measuring unit.

FIG. 52 is an explanatory diagram of the schematic block configurationand the operation of optical node device according to the seventeenthembodiment.

FIG. 53 is a block diagram of an optical node device comprising anoptical switch unit on the output side in an eighteenth embodiment.

FIG. 54 is a block diagram of an optical node device comprising theoptical switch unit on the input side in the eighteenth embodiment.

FIG. 55 is a block diagram of an optical node device comprising atrunk-type 3R relay unit in the eighteenth embodiment.

FIG. 56 shows a concept of 3R section information collection in opticalnode devices according to a nineteenth embodiment.

FIG. 57 shows a 3R section information collecting procedure in theoptical node device according to the nineteenth embodiment.

FIG. 58 shows a concept of 3R section information collection in theoptical node device according to the nineteenth embodiment.

FIG. 59 shows a 3R section information collecting procedure in theoptical node device according to the nineteenth embodiment.

FIG. 60 shows a concept of 3R section information collection in opticalnode devices of twentieth and twenty-ninth embodiments.

FIG. 61 is a block diagram of an optical node device according to thetwentieth and twenty-ninth embodiments.

FIG. 62 shows a concept of 3R section information collection in theoptical node devices according to the twentieth and twenty-ninthembodiments.

FIG. 63 is a block diagram of an optical node device according to thetwentieth and twenty-ninth embodiments.

FIG. 64 shows the relation of a network control device and optical nodedevices in a twenty-first embodiment.

FIG. 65 is a block diagram of the network control device according tothe twenty-first embodiment.

FIG. 66 is a block diagram of a maintenance-staff device according tothe twenty-first embodiment.

FIG. 67 is a block diagram of a network control device according to atwenty-second embodiment.

FIG. 68 is an explanatory diagram of an optical node device whichmeasures based on an instruction from the network control deviceaccording to the twenty-second embodiment.

FIG. 69 is a block diagram of a network control device according to thetwenty-second embodiment.

FIG. 70 is an explanatory diagram of the optical node device whichmeasures based on an instruction from the network control deviceaccording to the twenty-second embodiment.

FIG. 71 is a schematic block diagram of a network control deviceaccording to a twenty-third embodiment.

FIG. 72 is an explanatory diagram of traffic demand informationcollection in the network control device according to the twenty-thirdand twenty-fourth embodiments.

FIG. 73 is a schematic block diagram of the network control deviceaccording to the twenty-fourth embodiment.

FIG. 74 is an explanatory diagram of the schematic block configurationand the operation of an optical node device according to a twenty-fifthembodiment.

FIG. 75 is an explanatory diagram of the schematic block configurationand the operation of an optical node device according to thetwenty-fifth embodiment.

FIG. 76 is a block diagram of an optical node device comprising anoptical switch unit on the output side in a twenty-sixth embodiment.

FIG. 77 is a block diagram of an optical node device comprising theoptical switch unit on the input side in the twenty-sixth embodiment.

FIG. 78 is a block diagram of an optical node device comprising atrunk-type 3R relay unit according to the twenty-sixth embodiment.

FIG. 79 shows a concept of 3R section information collection in anoptical node device according to a twenty-seventh embodiment.

FIG. 80 shows a 3R section information collecting procedure in theoptical node device according to the twenty-seventh embodiment.

FIG. 81 shows a concept of 3R section information collection in theoptical node device according to the twenty-seventh embodiment.

FIG. 82 shows a 3R section information collecting procedure in theoptical node device according to the twenty-seventh embodiment.

FIG. 83 shows a concept of 3R section information collection in opticalnode devices according to a twenty-eighth embodiment.

FIG. 84 shows a 3R section information collecting procedure in theoptical node device according to the twenty-eighth embodiment.

FIG. 85 shows a concept of 3R section information collection in theoptical node device according to the twenty-eighth embodiment.

FIG. 86 shows a 3R section information collecting procedure in theoptical node device according to the twenty-eighth embodiment.

FIG. 87 shows a conventional optical network configuration.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereunder is a description of preferred embodiments according to thepresent invention, with the reference of drawings. However, the presentinvention is not limited to the respective embodiments below, and forexample, components of these embodiments may be appropriately combined.

Prior to describing the respective embodiments of the present invention,the denotation of a 3R section, a 3R source node, and a 3R destinationnode are described with reference to FIG. 1 to FIG. 3. FIG. 1 is anexplanatory diagram of the denotation of a 3R source node, a 3Rdestination node, and a 3R section. FIG. 2 is an explanatory diagram ofthe character of 3R sections. FIG. 3 shows an example of 3R sectioninformation corresponding to topology information of an optical network.As shown in FIG. 1, in the respective embodiments according to thepresent invention, a black circle denotes a 3R source node and a hatchedcircle denotes a 3R destination node.

Moreover, the section between optical node devices 2 and 5 is the 3Rsection. However, not every section between the optical node devices 2,3, 4, and 5 included therebetween is necessarily the 3R section. Thereason is that the capacity of the light emission element and the lightreceiving element of the respective optical node devices is notnecessarily uniform.

That is, in a case where an optical signal emitted from the lightemission element of the optical node device 2 is received by the lightreceiving element of the optical node device 5 without the necessity ofthe 3R relay partway, for example, assuming that the light emissionelement of the optical node device 3 can output only half the opticalsignal intensity or less compared to the light emission element of theoptical node device 2, the section between the optical node devices 3and 5 will not necessarily become the 3R section. Alternatively,assuming that the light receiving element of the optical node device 4has only half the light receiving sensitivity or less compared to thelight receiving element of the optical node device 5, the sectionbetween the optical node devices 2 and 4 will not necessarily become the3R section. Moreover, even in a section where the optical node device 5is the 3R source node and the optical node device 2 is the 3Rdestination node, the same light emission element or light receivingelement is not necessarily used for upstream and downstreamcommunication so that the optical signal intensity or the lightreceiving sensitivity may differ for each case, and hence it does notnecessarily become the 3R section. Therefore, as shown in FIG. 2, the 3Rsection may be denoted overlapping a part of or all of the other 3Rsections in some cases.

As shown in FIG. 3, the 3R section information that is set in suchmanner is denoted corresponding to the topology information of theoptical network. In the example of FIG. 3, optical node devices 1, 3,11, and 13 are specified as the 3R source nodes. The administrator ofthe optical network specifies such 3R source nodes; for example sourcenodes of an optical path having a large traffic demand are specified asthe 3R source nodes.

A one hop section between adjacent optical node devices obviouslyfunctions as the 3R section. However, in the present invention, asection between a 3R source node and a 3R destination node which hasbeen previously specified is set as the 3R section. Moreover, whensetting an optical path between optical node devices where the 3Rsection has not been previously set, there may be cases where the 3Rsection needs to be set temporarily. In such cases, the 3R section istemporarily set based on a predetermined determination policy. In such acase, the 3R section is set as an obvious 3R section one hop at a time.

Moreover, if it is possible to link between the source node and thedestination node with the same wavelength, wavelength conversion isunnecessary so that wavelength conversion resources can be used mosteffectively. However, the usage situation of the wavelength changes eachtime according to the wavelength usage situation in the overall opticalnetwork. Therefore there is no other way but to decide the optical nodedevice for converting the wavelength according to the wavelength vacancysituation at the time of the optical path setting request. However, in acase where an optical node device necessarily requiring wavelengthconversion is previously known, the optical node device is preferablyset as the 3R source node. Such cases where the optical node devicenecessarily requiring the wavelength conversion is previously known,includes a case, for example where the contents of the wavelengthconversion resources of a certain optical node device differ from thecontents of the wavelength conversion resources of the previous-hopoptical node device, so that optical path setting with the samewavelength is impossible in terms of hardware.

First Embodiment

Optical node devices of a first embodiment are described with referenceto FIG. 3 to FIG. 10. FIG. 4 is a schematic block diagram of an opticalnode device according to the first embodiment. FIG. 5 and FIG. 9 showoptical paths and 3R sections set in optical networks. FIG. 6 is a blockdiagram of a 3R relay implementation determining unit 21. FIG. 7 is anexplanatory diagram of the operation of a 3R implementation simulatingunit. FIG. 8 and FIG. 10 show signaling procedures according to thefirst embodiment when setting an optical path.

As shown in FIG. 4, the optical node device according to the firstembodiment comprises: a 3R section information storing unit 20 whichstores 3R section information corresponding to the topology informationof the optical network to which the optical node device itself belongsas shown in FIG. 3; and a 3R relay implementation determining unit 21which determines autonomously whether or not the optical node deviceitself is the optical node device for implementing the 3R relay when anoptical path passing through the optical node device itself is set, withreference to the 3R section information stored in the 3R sectioninformation storing unit 20.

In the first embodiment, since each optical node device determinesautonomously whether or not each optical node device itself is the 3Rrelay implementation node, each optical node device is required to storethe 3R section information respectively. However, the optical nodedevice not related to the optical path setting is not required to storethe 3R section information. Therefore if only the optical node device onthe route related to the optical path setting stores the 3R sectioninformation, the information storage resources can be effectively used.

Next is a description of the operation of the optical node deviceaccording to the first embodiment. Here, as shown in FIG. 5, is adescription of an example where an optical path from the optical nodedevice 1 to the optical node device 14 (double lines) is set. The 3Rrelay implementation determining unit 21 of the optical node device 1refers to the 3R section information storing unit 20 in order to knowwhat part the optical node device 1 is in the topology of the opticalnetwork. As a result, it recognizes that the optical node device 1 is asource node of the optical path to be set, so that the optical nodedevice 1 determines to implement the 3R relay.

An optical path setting unit 22 of the optical node device 1 receivesthe determination of the 3R relay implementation determining unit 21 andensures the resources for optical path setting and 3R relay. Then, asshown in FIG. 8, the optical path setting unit 22 loads a message ofDITR (Downstream Ingress Three R)=1 showing that the optical node device1 is the 3R source node, into the optical path setting request whensending the optical path setting request (Path) to the optical nodedevice 2.

The optical path setting unit 22 of the optical node device 2 whichreceives the optical path setting request (Path) from the optical nodedevice 1 queries the 3R relay implementation determining unit 21 as towhether or not the optical node device 2 is the optical node device forimplementing the 3R relay. The 3R relay implementation determining unit21 of the optical node device 2 refers to the 3R section informationstored in the 3R section information storing unit 20 and finds out thatthe optical node device 2 is not the 3R source node, and due to thedelivery of the DITR=1 from the optical node device 1, that the 3Rsection is up to the optical node device 4 if the optical node device 1is the 3R source node, so that the 3R relay implementation determiningunit 21 determines that optical node device 2 does not implement the 3Rrelay.

The optical path setting unit 22 of the optical node device 2 receivesthe determination of the 3R relay implementation determining unit 21 andensures the resources for optical path setting. Then, as shown in FIG.8, since the optical node device 2 does not implement the 3R relay, whensending the optical path setting request (Path) to the optical nodedevice 3, the optical path setting unit 22 loads the intact DITR=1 fromthe optical node device 1 into the optical path setting request.

The optical path setting unit 22 of the optical node device 3 whichreceives the optical path setting request (Path) from the optical nodedevice 2 queries the 3R relay implementation determining unit 21 as towhether or not the optical node device 3 is the optical node device forimplementing the 3R relay. The 3R relay implementation determining unit21 of the optical node device 3 refers to the 3R section informationstored in the 3R section information storing unit 20 and recognizes thatthe optical node device 3 may implement the 3R relay since it is the 3Rsource node on the 3R section from the optical node device 3 to theoptical node device 14, or that the optical node device 3 may notimplement the 3R relay but transmit the intact optical signal to theoptical node device 4 being the 3R destination node since it is not the3R source node on the 3R section from the optical node device 1 to theoptical node device 4.

In such a case, the 3R relay implementation determining unit 21 of theoptical node device 3 uses a 3R implementation simulating unit 23 and acomparison unit 24 shown in FIG. 6 to compare the number of 3Rimplementations with regards to the optical path from the optical nodedevice 3 to the optical node device 14 in the case where the opticalnode device 3 functions as the 3R source node, and the case where theoptical node device 3 does not function as the 3R source node. That is,as shown in FIG. 7, in the 3R implementation simulating unit 23, the 3Rsection is set for respective cases where the optical node device 3implements the 3R relay and the case where the optical node device 3does not implement the 3R relay. If the optical node device 3 performsthe 3R relay, then as shown in FIG. 7, there is 3R section informationwhere the optical node device 3 is the 3R source node and the opticalnode device 14 being the destination node is the 3R destination node, sothat one 3R section is set. Therefore, the number of 3R implementationsbecomes once.

If the optical node device 3 does not perform the 3R relay, the opticalnode device 4 becomes the 3R destination node. Here, the 3Rimplementation simulating unit 23 simulates the determination of the 3Rrelay implementation determining unit 21 of the optical node device 4.The determination policy of the 3R relay implementation determining unit21 of the optical node device 4 is “when the optical node device itselfis the optical node device corresponding to the 3R destination node andthe optical node device is not a destination node, the optical nodedevice determines that itself is the optical node device forimplementing the 3R relay using itself as the 3R source node and thenext-hop optical node device as the 3R destination node.”

That is, it simulates that, “the 3R relay implementation determiningunit 21 of the optical node device 4 determines that the optical nodedevice 4 itself is the optical node device corresponding to the 3Rdestination node and is not a destination node, so that the optical nodedevice 4 itself is the optical node device for implementing the 3R relayusing itself as the 3R source node and the next-hop optical node device5 as the 3R destination node.” Therefore, if the optical node device 4becomes the 3R destination node, the optical node device 4 determines toperform the 3R relay using the optical node device 4 as the 3R sourcenode and the next-hop optical node device 5 as the 3R destination node.

Next, the 3R implementation simulating unit 23 simulates thedetermination of the 3R relay implementation determining unit 21 of theoptical node device 5. The determination policy of the 3R relayimplementation determining unit 21 of the optical node device 5 is “whenthe optical node device 5 itself does not belong to any 3R sectionhaving a 3R source node on the optical path passing through the opticalnode device 5, it determines that the optical node device 5 itself isthe optical node device for implementing the 3R relay using the opticalnode device 5 itself as the 3R source node and the next-hop optical nodedevice as the 3R destination node”.

That is, it simulates that, “the 3R relay implementation determiningunit 21 of the optical node device 5 determines that the optical nodedevice 5 itself does not belong to any 3R section having a 3R sourcenode on the optical path passing through the optical node device 5itself, so that the optical node device 5 is the optical node device forimplementing the 3R relay using the optical node device 5 itself as the3R source node and the next-hop optical node device 14 as the 3Rdestination node”. Accordingly it is found that the optical node device5 implements 3R relay with the optical node device 5 as the 3R sourcenode and the next-hop optical node device 14 of the optical node device5 as the 3R destination node. Therefore, the number of 3Rimplementations becomes twice.

Such simulation results of the 3R implementation simulating unit 23 areinput into the comparison unit 24. In the comparison unit 24, it isfound that the number of 3R implementations can be reduced in the casewhere the optical node device 3 performs the 3R relay compared to thecase where the optical node device 3 does not perform the 3R relay.Therefore to that effect is output as a comparison result. In the 3Rrelay implementation determining unit 21, as a comparison result, thecase having the lower number of 3R implementations is selected.Therefore, the optical node device 3 determines that it performs the 3Rrelay.

In principle, such simulation is performed when, the one optical nodedevice is the 3R source node on any one of a plurality of 3R sectionsincluding the overlapped part on the optical paths passing through thisone optical node device, and this one optical node device does notcorrespond to the 3R source node or 3R destination node on any other 3Rsections. This is applied to the other embodiments.

The optical path setting unit 22 of the optical node device 3 receivesthe determination of the 3R relay implementation determining unit 21 andensures the resources for optical path setting and the 3R relay. Then,as shown in FIG. 8, the optical path setting unit 22 loads a message ofDITR=3 showing that the optical node device 3 is the 3R source node,into the optical path setting request when sending the optical pathsetting request (Path) to the optical node device 4.

The optical path setting unit 22 of the optical node device 4 whichreceives the optical path setting request (Path) from the optical nodedevice 3 queries the 3R relay implementation determining unit 21 as towhether or not the optical node device 4 is an optical node device forimplementing the 3R relay. The 3R relay implementation determining unit21 of the optical node device 4 refers to the 3R section informationstored in the 3R section information storing unit 20 and finds out thatthe optical node device 4 is the 3R destination node, and due to thedelivery of the DITR=3 from the optical node device 3, that the 3Rsection is up to the optical node device 14 if the optical node device 3is the 3R source node. Therefore the 3R relay implementation determiningunit 21 determines that the optical node device 4 is not required toperform the 3R relay.

The optical path setting unit 22 of the optical node device 4 receivesthe determination of the 3R relay implementation determining unit 21 andensures the resources for optical path setting. Then, since the opticalnode device 4 does not perform the 3R relay, as shown in FIG. 8, whensending the optical path setting request (Path) to the optical nodedevice 5, the optical path setting unit 22 loads the intact DITR=3 fromthe optical node device 3 into the optical path setting request.

The optical path setting unit 22 of the optical node device 5 whichreceives the optical path setting request (Path) from the optical nodedevice 4 queries the 3R relay implementation determining unit 21 as towhether or not the optical node device 5 is an optical node device forimplementing the 3R relay. The 3R relay implementation determining unit21 of the optical node device 5 refers to the 3R section informationstored in the 3R section information storing unit 20 and finds out thatthe optical node device 5 is not the 3R source node, and due to thedelivery of the DITR=3 from the optical node device 4, that the 3Rsection is up to the optical node device 14 if the optical node device 3is the 3R source node. Therefore the optical path setting unit 22determines that the optical node device 5 is not required to implementthe 3R relay.

The optical path setting unit 22 of the optical node device 5 receivesthe determination of the 3R relay implementation determining unit 21 andensures the resources for optical path setting. Then, since the opticalnode device 5 does not implement the 3R relay, as shown in FIG. 8, whensending the optical path setting request (Path) to the optical nodedevice 14, the optical path setting unit 22 loads the intact DITR=3 fromthe optical node device 4 into the optical path setting request.

The optical path setting unit 22 of the optical node device 14 whichreceives the optical path setting request (Path) from the optical nodedevice 5 queries the 3R relay implementation determining unit 21 as towhether or not the optical node device 14 is the optical node device forimplementing the 3R relay. The 3R relay implementation determining unit21 of the optical node device 14 refers to the 3R section informationstored in the 3R section information storing unit 20 and determines thatit is not required to implement the 3R relay since the optical nodedevice 14 is the destination node.

The optical path setting unit 22 of the optical node device 14 receivesthe determination of the 3R relay implementation determining unit 21 andensures the resources for optical path setting. Then, as shown in FIG.8, the optical path setting unit 22 sends the optical path settingcompletion notification (Resv) to the optical node device 5.

This optical path setting completion notification (Resv) is transmittedthrough the optical node devices 5->4->3->2->1 so that the optical pathsetting is completed. In this way, the respective optical node devices1, 2, 3, 4, 5, and 14 can determine autonomously whether or not theythemselves implement the 3R relay in the process of performing thesignaling procedure of the optical path setting.

Next is a description of another example of the operation of the opticalnode device according to the first embodiment. Here as shown in FIG. 9,is a description of an example where an optical path from the opticalnode device 1 to the optical node device 14 (double lines) is set. The3R relay implementation determining unit 21 of the optical node device 1refers to the 3R section information storing unit 20 in order to knowwhat part the optical node device 1 is in the topology of the opticalnetwork. As a result, the 3R relay implementation determining unit 21recognizes that the optical node device 1 is a source node of theoptical path to be set, and the 3R relay implementation determining unit21 determines that the optical node device 1 implements the 3R relay.

The optical path setting unit 22 of the optical node device 1 receivesthe determination of the 3R relay implementation determining unit 21 andensures the resources for optical path setting and the 3R relay. Then,as shown in FIG. 10, the optical path setting unit 22 loads a message ofDITR=1 showing that the optical node device 1 is the 3R source node,into the optical path setting request when sending the optical pathsetting request (Path) to the optical node device 10.

The optical path setting unit 22 of the optical node device 10 whichreceives the optical path setting request (Path) from the optical nodedevice 1 queries the 3R relay implementation determining unit 21 as towhether or not the optical node device 10 is the optical node device forimplementing the 3R relay. The 3R relay implementation determining unit21 of the optical node device 10 refers to the 3R section informationstored in the 3R section information storing unit 20 and finds out thatthe optical node device 10 is not the 3R source node, and due to thedelivery of the DITR=1 from the optical node device 1, that the 3Rsection is up to the optical node device 11 if the optical node device 1is the 3R source node. Therefore the 3R relay implementation determiningunit 21 determines that the optical node device 10 does not implementthe 3R relay.

The optical path setting unit 22 of the optical node device 10 receivesthe determination of the 3R relay implementation determining unit 21 andensures the resources for optical path setting. Then, since the opticalnode device 10 does not implement the 3R relay, as shown in FIG. 10,when sending the optical path setting request (Path) to the optical nodedevice 11, the optical path setting unit 22 loads the intact DITR=1 fromthe optical node device 1 into the optical path setting request.

The optical path setting unit 22 of the optical node device 11 whichreceives the optical path setting request (Path) from the optical nodedevice 10 queries the 3R relay implementation determining unit 21 as towhether or not the optical node device 11 is the optical node device forimplementing the 3R relay. The 3R relay implementation determining unit21 of the optical node device 11 refers to the 3R section informationstored in the 3R section information storing unit 20, and determinesthat the optical node device 11 implements the 3R relay since theoptical node device 11 is the 3R source node on the 3R section from theoptical node device 11 to the optical node device 13.

The optical path setting unit 22 of the optical node device 11 receivesthe determination of the 3R relay implementation determining unit 21 andensures the resources for optical path setting and the 3R relay. Then,as shown in FIG. 10, the optical path setting unit 22 loads a message ofDITR=11 showing that the optical node device 11 is the 3R source node,into the optical path setting request when sending the optical pathsetting request (Path) to the optical node device 12.

The optical path setting unit 22 of the optical node device 12 whichreceived the optical path setting request (Path) from the optical nodedevice 11 queries the 3R relay implementation determining unit 21 as towhether or not the optical node device 12 is the optical node device forimplementing the 3R relay. The 3R relay implementation determining unit21 of the optical node device 12 refers to the 3R section informationstored in the 3R section information storing unit 20, and determinesthat the optical node device 12 is not the 3R source node or 3Rdestination node, so that the optical node device 12 is not required toimplement the 3R relay.

The optical path setting unit 22 of the optical node device 12 receivesthe determination of the 3R relay implementation determining unit 21 andensures the resources for optical path setting. Then, since the opticalnode device 12 does not implement the 3R relay, as shown in FIG. 10,when sending the optical path setting request (Path) to the optical nodedevice 13, the optical path setting unit 22 loads the intact DITR=11from the optical node device 11 into the optical path setting request.

The optical path setting unit 22 of the optical node device 13 whichreceives the optical path setting request (Path) from the optical nodedevice 12 queries the 3R relay implementation determining unit 21 as towhether or not the optical node device 13 is the optical node device forimplementing the 3R relay. The 3R relay implementation determining unit21 of the optical node device 13 refers to the 3R section informationstored in the 3R section information storing unit 20, and determinesthat the optical node device 13 is the 3R source node, so that theoptical node device 13 implements the 3R relay.

The optical path setting unit 22 of the optical node device 13 receivesthe determination of the 3R relay implementation determining unit 21 andensures the resources for optical path setting and the 3R relay. Then,since the optical node device 13 implements the 3R relay, as shown inFIG. 10, when sending the optical path setting request (Path) to theoptical node device 14, the optical path setting unit 22 loads DITR=13into the optical path setting request.

The optical path setting unit 22 of the optical node device 14 whichreceives the optical path setting request (Path) from the optical nodedevice 13 queries the 3R relay implementation determining unit 21 as towhether or not the optical node device 14 is the optical node device forimplementing the 3R relay. The 3R relay implementation determining unit21 of the optical node device 14 refers to the 3R section informationstored in the 3R section information storing unit 20, and determinesthat the optical node device 14 is the destination node, so that theoptical node device 14 is not required to implement the 3R relay.

The optical path setting unit 22 of the optical node device 14 receivesthe determination of the 3R relay implementation determining unit 21 andensures the resources for optical path setting. Then, as shown in FIG.10, the optical path setting unit 22 sends the optical path settingcompletion notification (Resv) to the optical node device 13.

This optical path setting completion notification (Resv) is transmittedthrough the optical node devices 13->12->11->10->1 so that the opticalpath setting is completed. In this way, the respective optical nodedevices 1, 10, 11, 12, 13, and 14 can determine autonomously whether ornot they themselves implement the 3R relay in the process of performingthe signaling procedure of the optical path setting.

Second Embodiment

Optical node devices of a second embodiment according to the presentinvention are described with reference to FIG. 3, FIG. 5, FIG. 6, FIG.9, FIG. 11, FIG. 12, and FIG. 13. FIG. 11 is a schematic block diagramof an optical node device according to the second embodiment. FIG. 12and FIG. 13 show signaling procedures when setting an optical path inthe second embodiment.

The optical node device according to the second embodiment comprises: a3R section information storing unit 20 which stores 3R sectioninformation corresponding to the topology information of the opticalnetwork to which the optical node device itself belongs; a 3R relayimplementation node identifying unit 25 which identifies another opticalnode device for implementing the 3R relay among the other optical nodedevices through which an optical path passes from the optical nodedevice itself to the destination node when the optical node deviceitself is the source node, with reference to the 3R section informationstored in this 3R section information storing unit 20; and a 3R relayimplementation requesting unit 26 which requests 3R relay be implementedon the optical path where the optical node device itself is the sourcenode, to the other optical node device identified by this 3R relayimplementation node identifying unit 25.

In the second embodiment, since the optical node device corresponding tothe source node identifies the 3R relay implementation node, it issufficient if the optical node device corresponding to the source nodestores the 3R section information for the present, and it is notnecessary that all optical node devices or a plurality of optical nodedevices related to the optical path setting store the 3R sectioninformation similarly to the first embodiment. Therefore, if only theoptical node device corresponding to the source node stores the 3Rsection information, the information storage resources can beeffectively used.

Next is a description of the operation of the optical node deviceaccording to the second embodiment. The 3R section information shown inFIG. 3 is stored in the 3R section information storing unit 20. As shownin FIG. 5, the optical path setting unit 22 of the optical node device 1is about to attempt to set the optical path from the optical node device1 to the optical node device 14 (double lines), using the optical nodedevice 1 as the source node and the optical node device 14 as thedestination node. The optical path setting unit 22 requests the 3R relayimplementation node identifying unit 25 to identify the optical nodedevice for implementing the 3R relay except for the optical node device1 itself.

Here is a description of an identification algorithm of the optical nodedevice for implementing the 3R relay, in the 3R relay implementationnode identifying unit 25. Since the optical node device 2 is not the 3Rsource node and the optical node device 1 implements the 3R relay, it isdetermined that the optical node device 2 does not implement the 3Rrelay. Since the optical node device 3 is the 3R source node on the 3Rsection from the optical node device 3 to the optical node device 14,the 3R relay may be implemented. Alternatively, since the optical nodedevice 3 is not the 3R source node of the 3R section from the opticalnode device 1 to the optical node device 4, it may not implement the 3Rrelay, but transmit the intact optical signal to the optical node device4 being the 3R destination node.

In such a case, the 3R relay implementation node identifying unit 25uses the 3R implementation simulating unit 23 and the comparison unit 24shown in FIG. 6 to compare the number of 3R implementations in the casewhere the optical node device 3 functions as the 3R source node, and thecase where the optical node device 3 does not function as the 3R sourcenode, with regards to the optical path from the optical node device 3 tothe optical node device 14. The description hereunder is similar to thatof the first embodiment.

Such simulation results of the 3R implementation simulating unit 23 areinput into the comparison unit 24. In the comparison unit 24, it isfound that the number of 3R implementations can be reduced in the casewhere the optical node device 3 implements the 3R relay compared to thecase where the optical node device 3 does not implement the 3R relay.Therefore to that effect is output as a comparison result. The 3R relayimplementation node identifying unit 25 selects the case having thelower number of 3R implementations as a comparison result. Therefore, itis determined that the optical node device 3 implements the 3R relay.

Since the optical node device 4 is the 3R destination node, it isdetermined that the optical node device 4 does not implement the 3Rrelay. The optical node device 5 is not the source node so that it isdetermined that the optical node device does not implement the 3R relay.The optical node device 14 is the destination node so that it isdetermined that the optical node device 14 does not implement the 3Rrelay.

In this manner, the optical node device 1 being the source nodeidentifies the optical node device for implementing the 3R relay on theoptical path from the optical node device 1 to the optical node device14. Furthermore, the optical node device 1 outputs an ETR (ExplicitThree R)=3 as the 3R relay implementation request from the 3R relayimplementation requesting unit 26, to the optical node device 3 forimplementing the 3R relay identified by the optical node device 1itself.

When the optical node device for implementing the 3R relay can beidentified, then as shown in FIG. 12, the optical path setting unit 22of the optical node device 1 performs the signaling procedure of theoptical path setting. That is, the optical node device 1 ensures theresources for optical path setting and 3R relay, and sends the opticalpath setting request (Path) to the optical node device 2. At this time,ETR=3 is loaded into the optical path setting request.

The optical node device 2 which receives the optical path settingrequest (Path) from the optical node device 1 refers to ETR=3 torecognize that the optical node device 2 itself is not the optical nodedevice for implementing the 3R relay, ensures the resources for opticalpath setting, and sends the optical path setting request (Path) to theoptical node device 3. At this time, the intact ETR=3 delivered from theoptical node device 1 is loaded.

The optical node device 3 which receives the optical path settingrequest (Path) from the optical node device 2 refers to ETR=3 torecognize that the optical node device 3 itself is the optical nodedevice for implementing the 3R relay, ensures the resources for opticalpath setting and 3R relay, and sends the optical path setting request(Path) to the optical node device 4. At this time, since ETR=3 isdeleted after the optical node device 3 recognizes it is to implementthe 3R relay, ETR=3 is not transmitted to the nodes ahead of the opticalnode device 3.

The optical node device 4 which receives the optical path settingrequest (Path) from the optical node device 3 ensures the resources foroptical path setting, and sends the optical path setting request (Path)to the optical node device 5. The optical node device 5 which receivesthe optical path setting request (Path) from the optical node device 4ensures the resources for optical path setting, and sends the opticalpath setting request (Path) to the optical node device 14. The opticalnode device 14 which receives the optical path setting request (Path)from the optical node device 5 ensures the resources for optical pathsetting, and sends the optical path setting completion notification(Resv) to the optical node device 5. The optical path setting completionnotification (Resv) is transmitted through the optical node devices5->4->3->2->1 so that the optical path setting is completed.

Next is a description of another example of the operation of the opticalnode device according to the second embodiment. With reference to FIG. 9and FIG. 13, a description is given of an example of a case where the 3Rrelay is implemented twice on the optical path between the source nodeand the destination node. The 3R section information shown in FIG. 3 isstored in the 3R section information storing unit 20. As shown in FIG.9, the optical path setting unit 22 of the optical node device 1 isabout to attempt to set the optical path from the optical node device 1to the optical node device 14 (double lines), using the optical nodedevice 1 as the source node and the optical node device 14 as thedestination node. The optical path setting unit 22 requests the 3R relayimplementation node identifying unit 25 to identify the optical nodedevice for implementing the 3R relay except for the optical node device1 itself.

Here is a description of an identification algorithm of the optical nodedevice for implementing the 3R relay, in the 3R relay implementationnode identifying unit 25. Since the optical node device 10 is not the 3Rsource node and the optical node device 1 implements the 3R relay, it isdetermined that the optical node device 10 does not implement the 3Rrelay. Since the optical node device 11 is the 3R source node on the 3Rsection from the optical node device 11 to the optical node device 13,it is determined that the optical node device 11 implements the 3Rrelay. Since the optical node device 12 is not the 3R source node, it isdetermined that the optical node device 12 does not implement the 3Rrelay. Since the optical node device 13 is the 3R source node on the 3Rsection from the optical node device 13 to the optical node device 14,it is determined that the optical node device 13 implements the 3Rrelay. Since the optical node device 14 is the destination node, it isdetermined that the optical node device 14 does not implement the 3Rrelay.

In this manner, the optical node device 1 being the source nodeidentifies the optical node device for implementing the 3R relay on theoptical path from the optical node device 1 to the optical node device14. Furthermore, the optical node device 1 outputs an ETR=11, 13 as the3R relay implementation request from the 3R relay implementationrequesting unit 26, to the optical node device 3 for implementing the 3Rrelay identified by the optical node device 1 itself.

When the optical node device for implementing the 3R relay can beidentified, then as shown in FIG. 13, the optical path setting unit 22of the optical node device 1 performs the signaling procedure of theoptical path setting. That is, the optical node device 1 ensures theresources for the optical path setting and the 3R relay, and sends theoptical path setting request (Path) to the optical node device 10. Atthis time, ETR=11, 13 is loaded into the optical path setting request.

The optical node device 10 which receives the optical path settingrequest (Path) from the optical node device 1 refers to ETR=11, 13 torecognize that the optical node device 10 itself is not the optical nodedevice for implementing the 3R relay, ensures the resources for opticalpath setting, and sends the optical path setting request (Path) to theoptical node device 11. At this time, the intact ETR=11, 13 deliveredfrom the optical node device 1 is loaded.

The optical node device 11 which receives the optical path settingrequest (Path) from the optical node device 10 refers to ETR=11, 13 torecognize that the optical node device 11 itself is the optical nodedevice for implementing the 3R relay, ensures the resources for opticalpath setting and 3R relay, and sends the optical path setting request(Path) to the optical node device 12. At this time, since ETR=11 isdeleted after the optical node device 11 recognizes it is to implementthe 3R relay, ETR=13 is loaded into the optical path setting request.

The optical node device 12 which receives the optical path settingrequest (Path) from the optical node device 11 refers to ETR=13 torecognize that the optical node device 12 itself is not the optical nodedevice for implementing the 3R relay, ensures the resources for opticalpath setting, and sends the optical path setting request (Path) to theoptical node device 13. At this time, the intact ETR=13 delivered fromthe optical node device 11 is loaded.

The optical node device 13 which receives the optical path settingrequest (Path) from the optical node device 12 refers to ETR=13 torecognize that the optical node device 13 itself is the optical nodedevice for implementing the 3R relay, ensures the resources for opticalpath setting and 3R relay, and sends the optical path setting request(Path) to the optical node device 14. At this time, since ETR=13 isdeleted after the optical node device 13 recognizes it is to implementthe 3R relay, so that it is not transmitted to the optical node device14.

The optical node device 14 which receives the optical path settingrequest (Path) from the optical node device 13 ensures the resources foroptical path setting, and sends the optical path setting completionnotification (Resv) to the optical node device 13. The optical pathsetting completion notification (Resv) is transmitted through theoptical node devices 13->12->11>10->1 so that the optical path settingis completed.

In this manner, the optical node device being the source node identifiesthe optical node device for implementing the 3R relay on the opticalpath up to the destination node, so that other optical node devices onthis optical path may simply follow the instruction from the sourcenode, reducing the calculation load. Moreover, the optical node devicesexcept for the optical node device being the source node, do not have tostore the 3R section information, so that the information storageresources can be effectively used.

Third Embodiment

Optical node devices according to a third embodiment are described withreference to FIG. 4, FIG. 14, FIG. 15, FIG. 16, FIG. 18, and FIG. 19.FIG. 14 shows 3R section information according to the third embodiment.FIG. 15 and FIG. 18 show optical paths and 3R sections set in an opticalnetwork. FIG. 16 and FIG. 19 show signaling procedures when setting anoptical path in the third embodiment.

The third embodiment describes an example where the optical node devicefor implementing the 3R relay is set at the time of signaling, for bothof the upstream optical path and the downstream optical path on abi-directional optical path. The optical node device of the thirdembodiment is described as the configuration shown in FIG. 4. In theconfiguration shown in FIG. 4, each optical node device stores the same3R section information and determines autonomously whether or not eachoptical node device itself implements the 3R relay. The 3R sectioninformation shown in FIG. 14 is stored in the 3R section informationstoring unit 20.

In the third embodiment, similarly to the first embodiment, since eachoptical node device determines autonomously whether or not it is a nodefor implementing the 3R relay, each optical node device is required tostore the 3R section information respectively. However, the optical nodedevice not related to the optical path setting is not required to storethe 3R section information. Therefore if only the optical node device onthe route related to the optical path setting stores the 3R sectioninformation, the information storage resources can be effectively used.

Next is a description of the operation of the optical node deviceaccording to the third embodiment. Here as shown in FIG. 15, is adescription of an example where a bi-directional optical path from theoptical node device 1 to the optical node device 14 (double lines) isset. The 3R relay implementation determining unit 21 of the optical nodedevice 1 refers to the 3R section information storing unit 20 in orderto know what part the optical node device 1 is in the topology of theoptical network. As a result, the 3R relay implementation determiningunit 21 recognizes that the optical node device 1 is a source node onthe bi-directional optical path to be set, and is the 3R source node ofthe downstream optical path, and determines that the optical node device1 implements the 3R relay on the downstream optical path.

The optical path setting unit 22 of the optical node device 1 receivesthe determination of the 3R relay implementation determining unit 21 andensures the resources for downstream optical path setting and the 3Rrelay. Then, as shown in FIG. 16, the optical path setting unit 22 loadsa message of DITR=1 showing that the optical node device 1 is theoptical node device for implementing the 3R relay on the downstreamoptical path, into the optical path setting request when sending theoptical path setting request (Path) to the optical node device 2.

Furthermore, the 3R relay implementation determining unit 21 refers tothe 3R section information storing unit 20, and recognizes that theoptical node device 1 is the 3R destination node on the upstream opticalpath to be set, so that the 3R relay implementation determining unit 21determines that the optical node device 1 does not implement the 3Rrelay on the upstream optical path.

The optical path setting unit 22 of the optical node device 1 receivesthe determination of the 3R relay implementation determining unit 21 andensures the resources for upstream optical path setting. Then, as shownin FIG. 16, the optical path setting unit 22 loads a message of UETR(Upstream Egress Three R)=1 showing that the optical node device 1 isthe 3R destination node on the upstream optical path, into the opticalpath setting request when sending the optical path setting request(Path) to the optical node device 2.

The optical path setting unit 22 of the optical node device 2 whichreceives the optical path setting request (Path) from the optical nodedevice 1 queries the 3R relay implementation determining unit 21 as towhether or not the optical node device 2 is the optical node device forimplementing the 3R relay on the upstream or downstream optical path.The 3R relay implementation determining unit 21 of the optical nodedevice 2 refers to the 3R section information stored in the 3R sectioninformation storing unit 20 and finds out that the optical node device 2is not the 3R source node on the upstream or downstream optical path,and due to the delivery of the DITR=1 from the optical node device 1,that the 3R section is up to the optical node device 4 if the opticalnode device 1 is the 3R source node on the downstream optical path.Therefore, the 3R relay implementation determining unit 21 determinesthat the optical node device 2 does not implement the 3R relay.Moreover, the 3R relay implementation determining unit 21 finds out dueto the delivery of the UETR=1 from the optical node device 1, that theoptical node device 1 is the 3R destination node on the upstream opticalpath, and that the optical node device 4 is the 3R source node using theoptical node device 1 as the 3R destination node according to the 3Rsection information. Therefore, the 3R relay implementation determiningunit 21 determines that the optical node device 2 does not implement the3R relay on the upstream optical path neither.

The optical path setting unit 22 of the optical node device 2 receivesthe determination of the 3R relay implementation determining unit 21 andensures the resources for downstream and upstream optical path setting.Then, as shown in FIG. 16, since the optical node device 2 does notimplement the 3R relay, when sending the optical path setting request(Path) to the optical node device 3, the optical path setting unit 22loads the intact DITR=1 and UETR=1 from the optical node device 1 intothe optical path setting request.

The optical path setting unit 22 of the optical node device 3 whichreceives the optical path setting request (Path) from the optical nodedevice 2 queries the 3R relay implementation determining unit 21 as towhether or not the optical node device 3 is the optical node device forimplementing the 3R relay. The 3R relay implementation determining unit21 of the optical node device 3 refers to the 3R section informationstored in the 3R section information storing unit 20 and recognizes thatthe optical node device 3 may implement the 3R relay since it is the 3Rsource node on the 3R section from the optical node device 3 to theoptical node device 14 on the downstream optical path, or that theoptical node device 3 may not implement the 3R relay but transmit theintact optical signal to the optical node device 4 being the 3Rdestination node since it is not the 3R source node on the 3R sectionfrom the optical node device 1 to the optical node device 4 on thedownstream optical path.

In such a case, the 3R relay implementation determining unit 21 of theoptical node device 3 uses a 3R implementation simulating unit 23 and acomparison unit 24 to compare the number of 3R implementations in thecase where the optical node device 3 functions as the 3R source node,and the case where the optical node device 3 does not function as the 3Rsource node, with regards to the optical path from the optical nodedevice 3 to the optical node device 14. The description hereunder issimilar to that of the first embodiment.

Such simulation results of the 3R implementation simulating unit 23 areinput into the comparison unit 24. In the comparison unit 24, it isfound that the number of 3R implementations can be reduced in the casewhere the optical node device 3 implements the 3R relay on thedownstream optical path compared to the case where the optical nodedevice 3 does not implement the 3R relay. Therefore to that effect isoutput as a comparison result. The 3R relay implementation determiningunit 21 selects the case having the lower number of 3R implementationsas a comparison result. Therefore, the 3R relay implementationdetermining unit 21 determines that the optical node device 3 implementsthe 3R relay on the downstream optical path.

Furthermore, the 3R relay implementation determining unit 21 finds outthat the optical node device 3 is not the 3R source node on the upstreamoptical path, and due to the delivery of the UETR=1 from the opticalnode device 2, that the optical node device 4 is the 3R source node ifthe optical node device 1 is used as the 3R destination node, so thatthe 3R relay implementation determining unit 21 determines that the 3Rrelay is not implemented on the upstream optical path.

The optical path setting unit 22 of the optical node device 3 receivesthe determination of the 3R relay implementation determining unit 21 andensures the resources for optical path setting and the 3R relay. Then,as shown in FIG. 16, the optical path setting unit 22 loads a message ofDITR=3 showing that the optical node device 3 is the optical node devicefor implementing the 3R relay on the downstream optical path, into theoptical path setting request when sending the optical path settingrequest (Path) to the optical node device 4. Moreover, since the opticalnode device 3 does not implement the 3R relay on the upstream opticalpath, the intact UETR=1 delivered from the optical node device 2 isloaded into the optical path setting request.

The optical path setting unit 22 of the optical node device 4 whichreceives the optical path setting request (Path) from the optical nodedevice 3 queries the 3R relay implementation determining unit 21 as towhether or not the optical node device 4 is the optical node device forimplementing the 3R relay. The 3R relay implementation determining unit21 of the optical node device 4 refers to the 3R section informationstored in the 3R section information storing unit 20 and finds out thatthe optical node device 4 is the 3R destination node on the downstreamoptical path, and due to the delivery of the DITR=3 from the opticalnode device 3, that the 3R section is up to the optical node device 14if the optical node device 3 is the 3R source node on the downstreamoptical path, so that the 3R relay implementation determining unit 21determines that the optical node device 4 is not required to implementthe 3R relay.

Furthermore, the 3R relay implementation determining unit 21 refers tothe 3R section information stored in the 3R section information storingunit 20 and finds out due to the delivery of the UETR=1 from the opticalnode device 3, that the optical node device 4 is the 3R source node onthe upstream optical path using the optical node device 1 as the 3Rdestination node, so that the 3R relay implementation determining unit21 determines that the 3R relay is implemented on the upstream opticalpath.

The optical path setting unit 22 of the optical node device 4 receivesthe determination of the 3R relay implementation determining unit 21 andensures the resources for optical path setting and 3R relay. Then, asshown in FIG. 16, since the optical node device 4 does not implement the3R relay on the downstream optical path, when sending the optical pathsetting request (Path) to the optical node device 5, the optical pathsetting unit 22 loads the intact DITR=3 from the optical node device 3into the optical path setting request.

Moreover, since the optical node device 4 is the 3R source node but notthe destination node on the upstream optical path and neither the 3Rdestination node on the upstream optical path, the optical path settingunit 22 of the optical node device 4 loads UETR=4 as a message totransmit to the optical node device 5 that the optical node device 5 isthe 3R source node using the optical node device 4 as the 3R destinationnode, into the optical path setting request.

The optical path setting unit 22 of the optical node device 5 whichreceives the optical path setting request (Path) from the optical nodedevice 4 queries the 3R relay implementation determining unit 21 as towhether or not the optical node device 5 is the optical node device forimplementing the 3R relay. The 3R relay implementation determining unit21 of the optical node device 5 refers to the 3R section informationstored in the 3R section information storing unit 20 and finds out thatthe optical node device 5 is not the 3R source node on the downstreamoptical path, and due to the delivery of the DITR=3 from the opticalnode device 4, that the 3R section is up to the optical node device 14if the optical node device 3 is the 3R source node, so that the 3R relayimplementation determining unit 21 determines that the optical nodedevice 5 does not implement the 3R relay. Moreover, the 3R relayimplementation determining unit 21 refers to the 3R section informationand receives the UETR=4, and recognizes that the optical node device 5is the 3R source node using the optical node device 4 being atransmission source of the UETR=4 as the 3R destination node on theupstream optical path, and determines that the 3R relay is implementedon the upstream optical path.

The optical path setting unit 22 of the optical node device 5 receivesthe determination of the 3R relay implementation determining unit 21 andensures the resources for optical path setting and 3R relay. Then, asshown in FIG. 16, since the optical node device 5 does not implement the3R relay on the downstream optical path, when sending the optical pathsetting request (Path) to the optical node device 14, the optical pathsetting unit 22 loads the intact DITR=3 from the optical node device 4into the optical path setting request.

Moreover, the optical node device 5 is the 3R source node on theupstream optical path; however the 3R section using the optical nodedevice 14 as the 3R source node and the optical node device 5 as the 3Rdestination node is not set. In such a case, the optical node device 14is required to be the 3R source node based on the determination policyof “when the optical node device itself does not belong to any 3Rsection having the 3R source node on the optical path passing throughthe optical node device itself, it is determined that the optical nodedevice itself is the optical node device for implementing the 3R relayusing the optical node device itself as the 3R source node and thenext-hop optical node device of the optical node device itself as the 3Rdestination node.” Therefore, UETR=5 showing that the optical nodedevice 5 is the 3R destination node, is loaded into the optical pathrequest.

The optical path setting unit 22 of the optical node device 14 whichreceives the optical path setting request (Path) from the optical nodedevice 5 queries the 3R relay implementation determining unit 21 as towhether or not the optical node device 14 is the optical node device forimplementing the 3R relay. The 3R relay implementation determining unit21 of the optical node device 14 refers to the 3R section informationstored in the 3R section information storing unit 20 and determines thatit is not required to implement the 3R relay on the downstream opticalpath since the optical node device 14 is the destination node, but dueto the delivery of the UETR=5 from the optical node device 5 it isrequired to implement the 3R relay on the upstream optical path usingthe optical node device 14 as the 3R source node and the optical nodedevice 5 as the 3R destination node.

The optical path setting unit 22 of the optical node device 14 receivesthe determination of the 3R relay implementation determining unit 21 andensures the resources for optical path setting and 3R relay. Then, asshown in FIG. 16, the optical path setting unit 22 sends the opticalpath setting completion notification (Resv) to the optical node device5.

This optical path setting completion notification (Resv) is transmittedthrough the optical node devices 5->4->3->2->1 so that the optical pathsetting is completed. In this way, the respective optical node devices1, 2, 3, 4, 5, and 14 can determine autonomously whether or not theythemselves implement the 3R relay in the process of performing thesignaling procedure of the optical path setting.

Next is a description of another example of the operation of the opticalnode device according to the third embodiment. Here as shown in FIG. 18,is a description of an example where a bi-directional optical path fromthe optical node device 1 to the optical node device 14 (double lines)is set. The 3R relay implementation determining unit 21 of the opticalnode device 1 refers to the 3R section information storing unit 20 inorder to know what part the optical node device 1 is in the topology ofthe optical network. As a result, it is determined that the optical nodedevice 1 is a source node of the bi-directional optical path to be set,and is the 3R source node of the downstream optical path, and it isdetermined that the optical node device 1 implements the 3R relay on thedownstream optical path.

The optical path setting unit 22 of the optical node device 1 receivesthe determination of the 3R relay implementation determining unit 21 andensures the resources for downstream optical path setting and the 3Rrelay. Then, as shown in FIG. 19, the optical path setting unit 22 loadsa message of DITR=1 showing that the optical node device 1 is theoptical node device for implementing the 3R relay on the downstreamoptical path, into the optical path setting request when sending theoptical path setting request (Path) to the optical node device 10.

Furthermore, the 3R relay implementation determining unit 21 refers tothe 3R section information storing unit 20, and recognizes that theoptical node device 1 is the 3R destination node on the upstream opticalpath to be set, so that the 3R relay implementation determining unit 21determines that the optical node device 1 does not implement the 3Rrelay on the upstream optical path.

The optical path setting unit 22 of the optical node device 1 receivesthe determination of the 3R relay implementation determining unit 21 andensures the resources for upstream optical path setting. Then, as shownin FIG. 19, the optical path setting unit 22 loads a message of UETR=1showing that the optical node device 1 is the 3R destination node on theupstream optical path, into the optical path setting request whensending the optical path setting request (Path) to the optical nodedevice 10.

The optical path setting unit 22 of the optical node device 10 whichreceives the optical path setting request (Path) from the optical nodedevice 1 queries the 3R relay implementation determining unit 21 as towhether or not the optical node device 10 is the optical node device forimplementing the 3R relay on the upstream or downstream optical path.The 3R relay implementation determining unit 21 of the optical nodedevice 10 refers to the 3R section information stored in the 3R sectioninformation storing unit 20 and finds out that the optical node device10 is not the 3R source node on the upstream or downstream optical path,and due to the delivery of the DITR=1 from the optical node device 1,that the 3R section is up to the optical node device 11 if the opticalnode device 1 is the 3R source node on the downstream optical path, sothat the 3R relay implementation determining unit 21 determines that theoptical node device 10 does not implement the 3R relay. Moreover, the 3Rrelay implementation determining unit 21 finds out due to the deliveryof the UETR=1 from the optical node device 1, that the optical nodedevice 1 is the 3R destination node on the upstream optical path, andthat the optical node device 12 is the 3R source node using the opticalnode device 1 as the 3R destination node according to the 3R sectioninformation, so that the 3R relay implementation determining unit 21determines that the optical node device 10 does not implement the 3Rrelay on the upstream optical path neither.

The optical path setting unit 22 of the optical node device 10 receivesthe determination of the 3R relay implementation determining unit 21 andensures the resources for upstream and downstream optical path setting.Then, as shown in FIG. 19, since the optical node device 10 does notimplement the 3R relay, when sending the optical path setting request(Path) to the optical node device 11, the optical path setting unit 22loads the intact DITR=1 and UETR=1 from the optical node device 1 intothe optical path setting request.

The optical path setting unit 22 of the optical node device 11 whichreceives the optical path setting request (Path) from the optical nodedevice 10 queries the 3R relay implementation determining unit 21 as towhether or not the optical node device 11 is the optical node device forimplementing the 3R relay. The 3R relay implementation determining unit21 of the optical node device 11 refers to the 3R section informationstored in the 3R section information storing unit 20 and determines thatthe optical node device 11 implements the 3R relay since the opticalnode device 11 is the 3R source node on the 3R section from the opticalnode device 11 to the optical node device 13 on the downstream opticalpath.

Furthermore, the 3R relay implementation determining unit 21 finds outthat the optical node device 11 is not the 3R source node on theupstream optical path, and due to the delivery of the UETR=1 from theoptical node device 10, that the optical node device 12 is the 3R sourcenode if the optical node device 1 is used as the 3R destination node, sothat the 3R relay implementation determining unit 21 determines not toimplement the 3R relay on the upstream optical path.

The optical path setting unit 22 of the optical node device 11 receivesthe determination of the 3R relay implementation determining unit 21 andensures the resources for optical path setting and the 3R relay. Then,as shown in FIG. 19, the optical path setting unit 22 loads a message ofDITR=11 showing that the optical node device 11 is the optical nodedevice for implementing the 3R relay on the downstream optical path,into the optical path setting request when sending the optical pathsetting request (Path) to the optical node device 12. Moreover, sincethe optical node device 11 does not implement the 3R relay on theupstream optical path, the optical path setting unit 22 loads the intactUETR=1 delivered from the optical node device 10 into the optical pathsetting request.

The optical path setting unit 22 of the optical node device 12 whichreceives the optical path setting request (Path) from the optical nodedevice 11 queries the 3R relay implementation determining unit 21 as towhether or not the optical node device 12 is the optical node device forimplementing the 3R relay. The 3R relay implementation determining unit21 of the optical node device 12 refers to the 3R section informationstored in the 3R section information storing unit 20 and finds out thatthe optical node device 12 is the 3R destination node on the downstreamoptical path, and due to the delivery of the DITR=11 from the opticalnode device 11, that the 3R section is up to the optical node device 13if the optical node device 11 is the 3R source node on the downstreamoptical path, so that the 3R relay implementation determining unit 21determines that the optical node device 12 is not required to implementthe 3R relay.

Furthermore, the 3R relay implementation determining unit 21 refers tothe 3R section information stored in the 3R section information storingunit 20 and finds out due to the delivery of the UETR=1 from the opticalnode device 11 that the optical node device 12 is the 3R source node onthe upstream optical path using the optical node device 1 as the 3Rdestination node, so that the 3R relay implementation determining unit21 determines not to implement the 3R relay on the upstream opticalpath.

The optical path setting unit 22 of the optical node device 12 receivesthe determination of the 3R relay implementation determining unit 21 andensures the resources for optical path setting and 3R relay. Then, asshown in FIG. 19, since the optical node device 12 does not implementthe 3R relay on the downstream optical path, when sending the opticalpath setting request (Path) to the optical node device 13, the opticalpath setting unit 22 loads the intact DITR=11 from the optical nodedevice 11 into the optical path setting request.

Moreover, the optical node device 12 is the 3R source node on theupstream optical path and is the 3R destination node in the case wherethe optical node device 14 is the 3R source node on the upstream opticalpath. Therefore, the optical path setting unit 22 loads UETR=12 showingthat the optical node device 12 is the 3R destination node, into theoptical path setting request.

The optical path setting unit 22 of the optical node device 13 whichreceives the optical path setting request (Path) from the optical nodedevice 12 queries the 3R relay implementation determining unit 21 as towhether or not the optical node device 13 is the optical node device forimplementing the 3R relay. The 3R relay implementation determining unit21 of the optical node device 13 refers to the 3R section informationstored in the 3R section information storing unit 20 and finds out thatthe optical node device 13 is not the 3R source node on the downstreamoptical path, and due to the delivery of the DITR=11 from the opticalnode device 12, that the optical node device 13 is the 3R destinationnode if the optical node device 11 is the 3R source node.

Here, the determination is made based on the determination policy of“when the optical node device itself is the 3R destination node on thedownstream optical path, the optical node device itself is not thedestination node, and the optical node device itself is not the 3Rsource node on the downstream optical path, it is determined that theoptical node device itself is the optical node device for implementingthe 3R relay using the optical node device itself as the 3R source nodewhich uses the next-hop optical node device as the 3R destination nodeon the downstream optical path”, and then it is determined that theoptical node device 13 implements the 3R relay.

Moreover, on the upstream optical path, due to the delivery of theUETR=12, the 3R relay implementation determining unit 21 finds out thatthe section between the optical node device 14 and the optical nodedevice 12 is the 3R section, so that the 3R relay implementationdetermining unit 21 determines that the optical node device 13 does notimplement the 3R relay.

The optical path setting unit 22 of the optical node device 13 receivesthe determination of the 3R relay implementation determining unit 21 andensures the resources for optical path setting and 3R relay. Then, asshown in FIG. 19, since the optical node device 13 implements the 3Rrelay on the downstream optical path, when sending the optical pathsetting request (Path) to the optical node device 14, the optical pathsetting unit 22 loads DITR=13 into the optical path setting request.Moreover, since the optical node device 13 does not implement the 3Rrelay on the upstream optical path, the optical path setting unit 22loads the intact UETR=12 from the optical node device 12 into theoptical path setting request.

The optical path setting unit 22 of the optical node device 14 whichreceives the optical path setting request (Path) from the optical nodedevice 13 queries the 3R relay implementation determining unit 21 as towhether or not the optical node device 14 is the optical node device forimplementing the 3R relay. The 3R relay implementation determining unit21 of the optical node device 14 refers to the 3R section informationstored in the 3R section information storing unit 20 and determines thatit is not required to implement the 3R relay on the downstream opticalpath since the optical node device 14 is the destination node, but dueto the delivery of the UETR=12 from the optical node device 13, it isrequired to implement the 3R relay on the upstream optical path usingthe optical node device 14 as the 3R source node and the optical nodedevice 12 as the 3R destination node.

The optical path setting unit 22 of the optical node device 14 receivesthe determination of the 3R relay implementation determining unit 21 andensures the resources for optical path setting and 3R relay. Then, asshown in FIG. 19, the optical path setting unit 22 sends the opticalpath setting completion notification (Resv) to the optical node device13.

This optical path setting completion notification (Resv) is transmittedthrough the optical node devices 13->12->11->10->1 so that the opticalpath setting is completed. In this way, the respective optical nodedevices 1, 10, 11, 12, 13, and 14 can determine autonomously whether ornot they themselves implement the 3R relay in the process of performingthe signaling procedure of the optical path setting.

Fourth Embodiment

Optical node devices according to a fourth embodiment are described withreference to FIG. 11, FIG. 14, FIG. 15, FIG. 17, FIG. 18, and FIG. 20.FIG. 14 shows 3R section information according to the fourth embodimentused in common with the third embodiment. FIG. 15 and FIG. 18 showoptical paths and 3R sections set in an optical network used in commonwith the third embodiment. FIG. 17 and FIG. 20 show signaling procedureswhen setting an optical path in the fourth embodiment.

The fourth embodiment describes an example where the optical node devicefor implementing the 3R relay is set at the time of signaling, for bothof the upstream optical path and the downstream optical path on abi-directional optical path. The optical node device according to thefourth embodiment is described as the configuration shown in FIG. 11. Inthe configuration shown in FIG. 11, the optical node devicecorresponding to the source node identifies the optical node device forimplementing the 3R relay on the optical path up to the destinationnode, and requests this optical node device to implement the 3R relay.The 3R section information shown in FIG. 14 is stored in the 3R sectioninformation storing unit 20.

In the fourth embodiment, similarly to the second embodiment, since theoptical node device corresponding to the source node identifies the nodefor implementing the 3R relay, it is sufficient that the optical nodedevice corresponding to the source node stores the 3R sectioninformation for the present, and it is not necessary that all opticalnode devices or a plurality of optical node devices related to theoptical path setting store the 3R section information similarly to thethird embodiment. Therefore, if only the optical node devicecorresponding to the source node stores the 3R section information, theinformation storage resources can be effectively used.

Next is a description of the operation of the optical node deviceaccording to the fourth embodiment. Here as shown in FIG. 15, is adescription of an example where a bi-directional optical path from theoptical node device 1 to the optical node device 14 (double lines) isset. The 3R relay implementation node identifying unit 25 of the opticalnode device 1 corresponding to the source node refers to the 3R sectioninformation storing unit 20 in order to know what part the optical nodedevice 1 is in the topology of the optical network. As a result, the 3Rrelay implementation node identifying unit 25 recognizes that theoptical node device 1 is a source node on the bi-directional opticalpath to be set, and is the 3R source node of the downstream opticalpath, and determines that the optical node device 1 implements the 3Rrelay on the downstream optical path.

Furthermore, the 3R relay implementation node identifying unit 25 refersto the 3R section information storing unit 20, and recognizes that theoptical node device 1 is the 3R destination node on the upstream opticalpath to be set, so that the 3R relay implementation node identifyingunit 25 determines that the optical node device 1 does not implement the3R relay on the upstream optical path.

Moreover, the 3R relay implementation node identifying unit 25determines whether or not the optical node device 2 is the optical nodedevice for implementing the 3R relay on the upstream or downstreamoptical path. The 3R relay implementation node identifying unit 25refers to the 3R section information stored in the 3R sectioninformation storing unit 20 and finds out that the optical node device 2is not the 3R source node on the upstream or downstream optical path,and that the 3R section is up to the optical node device 4 if theoptical node device 1 is the 3R source node on the downstream opticalpath, so that the 3R relay implementation node identifying unit 25determines that the optical node device 2 does not implement the 3Rrelay. Furthermore, the 3R relay implementation node identifying unit 25finds out that the optical node device 1 is the 3R destination node onthe upstream optical path, and according to the 3R section information,that the optical node device 4 is the 3R source node using the opticalnode device 1 as the 3R destination node. Therefore, the 3R relayimplementation node identifying unit 25 determines that the optical nodedevice 2 does not implement the 3R relay on the upstream optical path.

Moreover, the 3R relay implementation node identifying unit 25determines whether or not the optical node device 3 is the optical nodedevice for implementing the 3R relay. The 3R relay implementation nodeidentifying unit 25 refers to the 3R section information stored in the3R section information storing unit 20 and recognizes that the opticalnode device 3 may implement the 3R relay since the optical node device 3is the 3R source node on the 3R section from the optical node device 3to the optical node device 14 on the downstream optical path, or thatthe optical node device 3 may not implement the 3R relay but transmitthe intact optical signal to the optical node device 4 being the 3Rdestination node since the optical node device 3 is not the 3R sourcenode on the 3R section from the optical node device 1 to the opticalnode device 4 on the downstream optical path.

In such a case, the 3R relay implementation node identifying unit 25uses the 3R implementation simulating unit 23 and the comparison unit 24to compare the number of 3R implementations in the case where theoptical node device 3 functions as the 3R source node, and the casewhere the optical node device 3 does not function as the 3R source node,with regards to the optical path from the optical node device 3 to theoptical node device 14. The description hereunder is similar to that ofthe first embodiment.

Such simulation results of the 3R implementation simulating unit 23 areinput into the comparison unit 24. In the comparison unit 24, it isfound that the number of 3R implementations can be reduced in the casewhere the optical node device 3 implements the 3R relay on thedownstream optical path compared to the case where the optical nodedevice 3 does not implement the 3R relay. Therefore, to that effect isoutput as a comparison result. As a comparison result, 3R relayimplementation node identifying unit 25 selects the case having thelower number of 3R implementations. Therefore, the optical node device 3determines to implement the 3R relay on the downstream optical path.

Furthermore, the 3R relay implementation node identifying unit 25 findsout that the optical node device 3 is not the 3R source node on theupstream optical path, and that the optical node device 4 is the 3Rsource node if the optical node device 1 is used as the 3R destinationnode, so that the 3R relay implementation node identifying unit 25determines not to implement the 3R relay on the upstream optical path.

Moreover, the 3R relay implementation node identifying unit 25determines whether or not the optical node device 4 is the optical nodedevice for implementing the 3R relay. The 3R relay implementation nodeidentifying unit 25 refers to the 3R section information stored in the3R section information storing unit 20 and finds out that the opticalnode device 4 is the 3R destination node on the downstream optical path,and that the 3R section is up to the optical node device 14 if theoptical node device 3 is the 3R source node on the downstream opticalpath, so that the 3R relay implementation node identifying unit 25determines that the optical node device 4 is not required to implementthe 3R relay.

Furthermore, the 3R relay implementation node identifying unit 25 refersto the 3R section information stored in the 3R section informationstoring unit 20 and finds out that the optical node device 4 is the 3Rsource node on the upstream optical path using the optical node device 1as the 3R destination node, so that the 3R relay implementation nodeidentifying unit 25 determines to implement the 3R relay on the upstreamoptical path.

The 3R relay implementation node identifying unit 25 determines whetheror not the optical node device 5 is the optical node device forimplementing the 3R relay. The 3R relay implementation node identifyingunit 25 refers to the 3R section information stored in the 3R sectioninformation storing unit 20 and finds out that the optical node device 5is not the 3R source node on the downstream optical path, and that the3R section is up to the optical node device 14 if the optical nodedevice 3 is the 3R source node, so that the 3R relay implementation nodeidentifying unit 25 determines that the optical node device 5 does notimplement the 3R relay. Moreover, the 3R relay implementation nodeidentifying unit 25 recognizes that the optical node device 5 is the 3Rsource node on the upstream optical path, and determines to implementthe 3R relay on the upstream optical path.

The 3R relay implementation node identifying unit 25 determines whetheror not the optical node device 14 is the optical node device forimplementing the 3R relay. The 3R relay implementation node identifyingunit 25 refers to the 3R section information stored in the 3R sectioninformation storing unit 20 and determines that it is not required toimplement the 3R relay on the downstream optical path since that theoptical node device 14 is the destination node, but it is required toimplement the 3R relay on the upstream optical path using the opticalnode device 14 as the 3R source node.

The reason is such that: the optical node device 5 is the 3R source nodeon the upstream optical path; however the 3R section using the opticalnode device 14 as the 3R source node and the optical node device 5 asthe 3R destination node is not set. In such a case, the optical nodedevice 14 is required to be the 3R source node based on thedetermination policy of “when the optical node device itself does notbelong to any 3R section having the 3R source node on the optical pathpassing through the optical node device itself, it is determined thatthe optical node device itself is the optical node device forimplementing the 3R relay using the optical node device itself as the 3Rsource node and the next-hop optical node device of the optical nodedevice itself as the 3R destination node.”

In this manner, the optical node device 1 being the source nodeidentifies the optical node device for implementing the 3R relay on theoptical path from the optical node device 1 to the optical node device14. Furthermore, the 3R relay implementation requesting unit 26 of theoptical node device 1 outputs DExTR (Downstream Explicit Three R)=3 andUExTR (Upstream Explicit Three R)=4, 5, 14 as the 3R relayimplementation request on the downstream and upstream optical paths,respectively, to the optical node device 3 for implementing the 3R relayidentified by the optical node device 1 itself.

When the optical node device for implementing the 3R relay can beidentified, then as shown in FIG. 17, the optical path setting unit 22of the optical node device 1 performs the signaling procedure of theoptical path setting. That is, the optical node device 1 ensures theresources for optical path setting and 3R relay, and sends the opticalpath setting request (Path) to the optical node device 2. At this time,DExTR=3 and UExTR=4, 5, 14 are loaded into the optical path settingrequest.

The optical node device 2 which receives the optical path settingrequest (Path) from the optical node device 1 refers to DExTR=3 andUExTR=4, 5, 14 to recognize that the optical node device 2 itself is notthe optical node device for implementing the 3R relay, ensures theresources for optical path setting, and sends the optical path settingrequest (Path) to the optical node device 3. At this time, the intactDExTR=3 and UExTR=4, 5, 14 delivered from the optical node device 1 areloaded.

The optical node device 3 which receives the optical path settingrequest (Path) from the optical node device 2 refers to DExTR=3 andUExTR=4, 5, 14 to recognize that the optical node device 3 itself is theoptical node device for implementing the 3R relay on the downstreamoptical path, ensures the resources for optical path setting and 3Rrelay, and sends the optical path setting request (Path) to the opticalnode device 4. At this time, since DExTR=3 is deleted after the opticalnode device 3 recognizes to implement the 3R relay, UExTR=4, 5, 14 areloaded into the optical path setting request.

The optical node device 4 which receives the optical path settingrequest (Path) from the optical node device 3 refers to UExTR=4, 5, 14to recognize that the optical node device 4 itself is the optical nodedevice for implementing the 3R relay on the upstream optical path,ensures the resources for optical path setting and 3R relay, and sendsthe optical path setting request (Path) to the optical node device 5. Atthis time, since UExTR=4 is deleted after the optical node device 4recognizes to implement the 3R relay, UExTR=5, 14 are loaded into theoptical path setting request.

The optical node device 5 which receives the optical path settingrequest (Path) from the optical node device 4 refers to UExTR=5, 14 torecognize that the optical node device 5 itself is the optical nodedevice for implementing the 3R relay on the upstream optical path,ensures the resources for optical path setting and 3R relay, and sendsthe optical path setting request (Path) to the optical node device 14.At this time, since UExTR=5 is deleted after the optical node device 5recognizes to implement the 3R relay, UExTR=14 is loaded into theoptical path setting request.

The optical node device 14 which receives the optical path settingrequest (Path) from the optical node device 5 refers to UExTR=14 torecognize that the optical node device 14 itself is the optical nodedevice for implementing the 3R relay on the upstream optical path,ensures the resources for optical path setting and 3R relay, and sendsthe optical path setting completion notification (Resv) to the opticalnode device 5. The optical path setting completion notification (Resv)is transmitted through the optical node devices 5->4->3->2->1 so thatthe optical path setting is completed.

In this manner, the optical node device being the source node identifiesthe optical node device for implementing the 3R relay on thebi-directional optical path up to the destination node, so that theother optical node devices on this bi-directional optical path maysimply follow the instruction from the source node, reducing thecalculation load. Moreover, the optical node devices except for theoptical node device being the source node, do not have to store the 3Rsection information, so that the information storage resources can beeffectively used.

Next is a description of another example of the operation of the opticalnode device according to the fourth embodiment. Here as shown in FIG.18, is a description of an embodiment where a bi-directional opticalpath from the optical node device 1 to the optical node device 14(double lines) is set. The 3R relay implementation node identifying unit25 of the optical node device 1 corresponding to the source node refersto the 3R section information storing unit 20 in order to know what partthe optical node device 1 is in the topology of the optical network. Asa result, the 3R relay implementation node identifying unit 25recognizes that the optical node device 1 is a source node on thebi-directional optical path to be set, and is the 3R source node of thedownstream optical path, and determines that the optical node device 1implements the 3R relay on the downstream optical path.

Furthermore, the 3R relay implementation node identifying unit 25 refersto the 3R section information storing unit 20, and recognizes that theoptical node device 1 is the 3R destination node on the upstream opticalpath to be set, so that the 3R relay implementation node identifyingunit 25 determines that the optical node device 1 does not implement the3R relay on the upstream optical path.

Moreover, the 3R relay implementation node identifying unit 25determines whether or not the optical node device 10 is the optical nodedevice for implementing the 3R relay on the upstream or downstreamoptical path. The 3R relay implementation node identifying unit 25refers to the 3R section information stored in the 3R sectioninformation storing unit 20 and finds out that the optical node device10 is not the 3R source node on the upstream or downstream optical path,and that the 3R section is up to the optical node device 11 if theoptical node device 1 is the 3R source node on the downstream opticalpath, so that the 3R relay implementation node identifying unit 25determines that the optical node device 10 does not implement the 3Rrelay. Furthermore, the 3R relay implementation node identifying unit 25finds out that the optical node device 1 is the 3R destination node onthe upstream optical path, and according to the 3R section information,that the optical node device 12 is the 3R source node using the opticalnode device 1 as the 3R destination node. Therefore, the 3R relayimplementation node identifying unit 25 determines that the optical nodedevice 10 does not implement the 3R relay on the upstream optical path.

Furthermore, the 3R relay implementation node identifying unit 25determines whether or not the optical node device 11 is the optical nodedevice for implementing the 3R relay. The 3R relay implementation nodeidentifying unit 25 refers to the 3R section information stored in the3R section information storing unit 20, and determines that the opticalnode device 11 implements the 3R relay since the optical node device 11is the 3R source node on the 3R section from the optical node device 11to the optical node device 13 on the downstream optical path.Furthermore, the 3R relay implementation node identifying unit 25 findsout that the optical node device 11 is not the 3R source node on theupstream optical path, and that the optical node device 12 is the 3Rsource node if the optical node device 1 is used as the 3R destinationnode, so that the 3R relay implementation node identifying unit 25determines not to implement the 3R relay on the upstream optical path.

Moreover the 3R relay implementation node identifying unit 25 finds outthat the optical node device 12 is neither the 3R source node nor the 3Rdestination node on the downstream optical path, and that the 3R sectionis up to the optical node device 13 if the optical node device 11 is the3R source node on the downstream optical path, so that the 3R relayimplementation node identifying unit 25 determines that the optical nodedevice 12 is not required to implement the 3R relay. Furthermore, the 3Rrelay implementation node identifying unit 25 finds out that the opticalnode device 12 is the 3R source node on the upstream optical path usingthe optical node device 1 as the 3R destination node, so that the 3Rrelay implementation node identifying unit 25 determines to implementthe 3R relay on the upstream optical path.

The 3R relay implementation node identifying unit 25 finds out that theoptical node device 13 is not the 3R source node on the downstreamoptical path, and that the optical node device 13 is the 3R destinationnode if the optical node device 11 is the 3R source node. Here, thedetermination is made based on the determination policy of “when oneoptical node device is the optical node device corresponding to the 3Rdestination node and is not a destination node, it is determined thatthe one optical node device is the optical node device for implementingthe 3R relay using the one optical node device as the 3R source node andthe next-hop optical node device as the 3R destination node”, and it isdetermined that the optical node device 13 implements the 3R relay.Furthermore, the 3R relay implementation node identifying unit 25 findsout that the section between the optical node device 14 and the opticalnode device 12 is the 3R section on the upstream optical path, so thatthe 3R relay implementation node identifying unit 25 determines that theoptical node device 13 does not implement the 3R relay.

Moreover, the 3R relay implementation node identifying unit 25determines that it is not required to implement the 3R relay on thedownstream optical path since the optical node device 14 is thedestination node, but it is required to implement the 3R relay on theupstream optical path using the optical node device 14 as the 3R sourcenode and the optical node device 12 as the 3R destination node.

In this manner, the optical node device 1 being the source nodeidentifies the optical node device for implementing the 3R relay on theoptical path from the optical node device 1 to the optical node device14. Furthermore, the 3R relay implementation requesting unit 26 of theoptical node device 1 outputs DExTR=11, 13 and UExTR=12, 14 as the 3Rrelay implementation request on the downstream and upstream opticalpaths, respectively, to the optical node device 3 for implementing the3R relay identified by the optical node device 1 itself.

When the optical node device for implementing the 3R relay can beidentified, then as shown in FIG. 20, the optical path setting unit 22of the optical node device 1 performs the signaling procedure of theoptical path setting. That is, the optical node device 1 ensures theresources for optical path setting and 3R relay, and sends the opticalpath setting request (Path) to the optical node device 10. At this time,DExTR=11, 13 and UExTR=12, 14 are loaded into the optical path settingrequest.

The optical node device 10 which receives the optical path settingrequest (Path) from the optical node device 1 refers to DExTR=11, 13 andUExTR=12, 14 to recognize that the optical node device 10 itself is notthe optical node device for implementing the 3R relay, ensures theresources for optical path setting, and sends the optical path settingrequest (Path) to the optical node device 11. At this time, the intactDExTR=11, 13 and UExTR=12, 14 delivered from the optical node device 1are loaded.

The optical node device 11 which receives the optical path settingrequest (Path) from the optical node device 10 refers to DExTR=11, 13and UExTR=12, 14 to recognize that the optical node device 11 itself isthe optical node device for implementing the 3R relay on the downstreamoptical path, ensures the resources for optical path setting and 3Rrelay, and sends the optical path setting request (Path) to the opticalnode device 12. At this time, since DExTR=1 is deleted after the opticalnode device 3 recognizes to implement the 3R relay, DExTR=13 andUExTR=12, 14 are loaded into the optical path setting request.

The optical node device 12 which receives the optical path settingrequest (Path) from the optical node device 11 refers to DExTR=13 andUExTR=12, 14 to recognize that the optical node device 12 itself is theoptical node device for implementing the 3R relay on the upstreamoptical path, ensures the resources for optical path setting and 3Rrelay, and sends the optical path setting request (Path) to the opticalnode device 13. At this time, since UExTR=12 is deleted after theoptical node device 12 recognizes to implement the 3R relay, DExTR=13and UExTR=14 are loaded into the optical path setting request.

The optical node device 13 which receives the optical path settingrequest (Path) from the optical node device 12 refers to DExTR=13 andUExTR=14 to recognize that the optical node device 13 itself is theoptical node device for implementing the 3R relay on the downstreamoptical path, ensures the resources for optical path setting and 3Rrelay, and sends the optical path setting request (Path) to the opticalnode device 14. At this time, since DExTR=13 is deleted after theoptical node device 13 recognizes to implement the 3R relay, UExTR=14 isloaded into the optical path setting request.

The optical node device 14 which receives the optical path settingrequest (Path) from the optical node device 13 refers to UExTR=14 torecognize that the optical node device 14 itself is the optical nodedevice for implementing the 3R relay on the upstream optical path,ensures the resources for optical path setting and 3R relay, and sendsthe optical path setting completion notification (Resv) to the opticalnode device 13. The optical path setting completion notification (Resv)is transmitted through the optical node devices 13->12->11->10->1 sothat the optical path setting is completed.

In this manner, the optical node device being the source node identifiesthe optical node device for implementing the 3R relay on thebi-directional optical path up to the destination node, so that theother optical node devices on this bi-directional optical path maysimply follow the instruction from the source node, reducing thecalculation load. Moreover, the optical node devices except for theoptical node device being the source node, do not have to store the 3Rsection information, so that the information storage resources can beeffectively used.

Fifth Embodiment

Optical node devices according to a fifth embodiment are described withreference to FIG. 3, FIG. 4, FIG. 5, FIG. 9, and FIG. 21 to FIG. 26.FIG. 21, FIG. 22, FIG. 24, and FIG. 25 show 3R section information inthe optical node devices according to the fifth embodiment. FIG. 23 andFIG. 26 show signaling procedures when setting an optical path in thefifth embodiment.

As shown in FIG. 4, the optical node device according to the fifthembodiment comprises: a 3R section information storing unit 20 whichstores 3R section information using the optical node device itself asthe 3R source node; and a 3R relay implementation determining unit 21which receives a message included in an optical path setting requestshowing that the optical node device itself is the 3R destination node,then, when the optical node device itself is not the destination node,refers to the 3R section information storing unit 20 and determines thatitself is the optical node device for implementing the 3R relay if theoptical node device itself is the 3R source node on this optical path.Moreover, the optical path setting unit 22 sends a message to transmitto the optical node device corresponding to the 3R destination node ofthe 3R section on the optical path using the optical node device itselfas the 3R source node, that this optical node device corresponding tothe 3R destination node of the 3R section is the 3R destination node.

The 3R relay implementation determining unit 21 receives a messageincluded in an optical path setting request showing that the opticalnode device itself is the 3R destination node, then when the opticalnode device itself is not the destination node, refers to the 3R sectioninformation storing unit 20 and determines that the optical node deviceitself is the optical node device for implementing the 3R relay usingthe optical node device itself as the 3R source node and the next-hopoptical node device as the 3R destination node if the optical nodedevice itself is not the 3R source node on this optical path. Moreover,the optical path setting unit 22 sends a message to transmit to thenext-hop optical node device that this next-hop optical node device isthe 3R destination node.

In the fifth embodiment, the optical node device corresponding to the 3Rsource node stores the 3R section information of this 3R source node.Since it does not store other 3R section information, the informationstorage resources can be effectively used.

Next is a description of the operation of the optical node deviceaccording to the fifth embodiment. Here as shown in FIG. 5, is adescription of an example where an optical path from the optical nodedevice 1 to the optical node device 14 (double lines) is set. The 3Rrelay implementation determining unit 21 of the optical node device 1corresponding to the 3R source node recognizes that an optical pathsetting request using the optical node device 1 as the source node hasissued, and determines that the optical node device 1 implements the 3Rrelay on the optical path. Moreover, the 3R section information storingunit 20 stores the 3R section information shown in FIG. 21, so that the3R relay implementation determining unit 21 recognizes that if using theoptical node device 1 as the 3R source node, the 3R destination node isthe optical node device 4.

As shown in FIG. 23, the optical path setting unit 22 which has beennotified of the recognition result of the 3R relay implementationdetermining unit 21 generates DITR=1 as a message showing that theoptical node device 1 is the 3R source node, and DETR=4 as a messageshowing that the optical node device 4 is the 3R destination node. Theoptical path setting unit 22 ensures the resources for optical pathsetting and the 3R relay, and loads DITR=1 and DETR=4 when sending theoptical path setting request (Path) to the optical node device 2.

The 3R relay implementation determining unit 21 of the optical nodedevice 2 which receives the optical path setting request (Path) from theoptical node device 1 refers to the DITR=1 and DETR=4 to recognize thatthe optical node device 2 itself is not the optical node device forimplementing the 3R relay. The optical path setting unit 22 of theoptical node device 2 ensures the resources for optical path setting,and loads the intact DITR=1 and DETR=4 from the optical node device 1when sending the optical path setting request (Path) to the optical nodedevice 3.

The 3R relay implementation determining unit 21 of the optical nodedevice 3 which receives the optical path setting request (Path) from theoptical node device 2 refers to the DITR=1 and DETR=4. Furthermore the3R section information storing unit 20 stores the 3R section informationshown in FIG. 22 since the optical node device 3 is the 3R source node,and the 3R relay implementation determining unit 21 refers to this 3Rsection information. The message included in the optical path settingrequest is DETR=4 specifying that the optical node device 4 is the 3Rdestination node. However the 3R relay implementation determining unit21 determines whether or not the optical node device 3 is the opticalnode device for implementing the 3R relay.

The 3R relay implementation determining unit 21 refers to the 3R sectioninformation stored in the 3R section information storing unit 20 andrecognizes that the optical node device 3 may implement the 3R relaysince the optical node device 3 is the 3R source node on the 3R sectionfrom the optical node device 3 to the optical node device 14, or thatthe optical node device 3 may not implement the 3R relay but transmitthe intact optical signal to the optical node device 4 being the 3Rdestination node since the optical node device is not the 3R source nodeon the 3R section from the optical node device 1 to the optical nodedevice 4.

In such a case, the 3R relay implementation determining unit 21 uses a3R implementation simulating unit 23 and a comparison unit 24 to comparethe number of 3R implementations in the case where the optical nodedevice 3 functions as the 3R source node, and the case where the opticalnode device 3 does not function as the 3R source node, with regards tothe optical path from the optical node device 3 to the optical nodedevice 14. The description hereunder is similar to that of the firstembodiment.

Such simulation results of the 3R implementation simulating unit 23 areinput into the comparison unit 24. In the comparison unit 24, it isfound that the number of 3R implementations can be reduced in the casewhere the optical node device 3 implements the 3R relay compared to thecase where the optical node device 3 does not implement the 3R relay.Therefore to that effect is output as a comparison result. As acomparison result, the 3R relay implementation determining unit 21selects the case having the lower number of 3R implementations.Therefore, the optical node device 3 determines to implement the 3Rrelay.

In response to this determination, the optical path setting unit 22ensures the resources for optical path setting and the 3R relay, and asshown in FIG. 23 it loads DITR=3 and DETR=14 as a message showing thatthe optical node device 3 is the 3R source node and the optical nodedevice 14 is the 3R destination node, when sending the optical pathsetting request (Path) to the optical node device 4.

The 3R relay implementation determining unit 21 of the optical nodedevice 4 which receives the optical path setting request (Path) from theoptical node device 3 refers to the DITR=3 and DETR=14 to recognize thatthe optical node device 4 itself is not the optical node device forimplementing the 3R relay. The optical path setting unit 22 of theoptical node device 4 ensures the resources for optical path setting,and loads the intact DITR=3 and DETR=14 from the optical node device 3when sending the optical path setting request (Path) to the optical nodedevice 5.

The 3R relay implementation determining unit 21 of the optical nodedevice 5 which receives the optical path setting request (Path) from theoptical node device 4 refers to the DITR=3 and DETR=14 to recognize thatthe optical node device 5 itself is not the optical node device forimplementing the 3R relay. The optical path setting unit 22 of theoptical node device 5 ensures the resources for optical path setting,and loads the intact DITR=3 and DETR=14 from the optical node device 4when sending the optical path setting request (Path) to the optical nodedevice 14.

The 3R relay implementation determining unit 21 of the optical nodedevice 14 which receives the optical path setting request (Path) fromthe optical node device 5 refers to the DITR=3 and DETR=14 to recognizethat itself is the 3R destination node. Furthermore, based on thedetermination policy of “when the optical node device itself is theoptical node device corresponding to the 3R destination node on theoptical path and is not a destination node, it requests the next-hopoptical node device to implement the 3R relay using the optical nodedevice itself as the 3R source node and the next-hop optical node deviceas the 3R destination node”, the 3R relay implementation determiningunit 21 determines whether or not the optical node device 14 itselfimplements the 3R relay. The 3R relay implementation determining unit 21refers to the optical path setting request and recognizes that theoptical node device 14 itself is the destination node, so that the 3Rrelay implementation determining unit 21 determines that it is notrequired to implement the 3R relay.

The optical path setting unit 22 of the optical node device 14 ensuresthe resources for optical path setting and sends the optical pathsetting completion notification (Resv) to the optical node device 5. Theoptical path setting completion notification (Resv) is transmittedthrough the optical node devices 5->4->3->2->1 so that the optical pathsetting is completed.

Next is a description of another example of the operation of the opticalnode device of the fifth embodiment. Here as shown in FIG. 9, is adescription of an example where an optical path from the optical nodedevice 1 to the optical node device 14 (double lines) is set. The 3Rrelay implementation determining unit 21 of the optical node device 1corresponding to the 3R source node recognizes that an optical pathsetting request using the optical node device 1 as the source node hasissued, and the optical node device 1 determines to implement the 3Rrelay on the optical path. Moreover, the 3R section information storingunit 20 stores the 3R section information shown in FIG. 21, so that the3R relay implementation determining unit 21 can recognize that the 3Rdestination node using the optical node device 1 as the 3R source nodeis the optical node device 11.

The optical path setting unit 22 which has been notified of therecognition result of the 3R relay implementation determining unit 21generates DITR=1 as a message showing that the optical node device 1 isthe 3R source node, and DETR=11 as a message showing that the opticalnode device 11 is the 3R destination node. The optical path setting unit22 ensures the resources for optical path setting and the 3R relay, andas shown in FIG. 26, loads DITR=1 and DETR=11 when sending the opticalpath setting request (Path) to the optical node device 10.

The optical node device 10 which receives the optical path settingrequest (Path) from the optical node device 1 refers to the DITR=1 andDETR=11 to recognize that the optical node device 10 itself is not theoptical node device for implementing the 3R relay. The optical pathsetting unit 22 of the optical node device 10 ensures the resources foroptical path setting, and loads the intact DITR=1 and DETR=11 from theoptical node device 1 when sending the optical path setting request(Path) to the optical node device 11.

The 3R relay implementation determining unit 21 of the optical nodedevice 11 which receives the optical path setting request (Path) fromthe optical node device 10 refers to the DITR=1 and DETR=11.Furthermore, the 3R section information storing unit 20 stores the 3Rsection information shown in FIG. 24 since the optical node device 11 isthe 3R source node, and thus the 3R relay implementation determiningunit 21 refers to this 3R section information. Therefore, the 3R relayimplementation determining unit 21 recognizes that the optical nodedevice 11 itself is the 3R destination node and the 3R source node ofthe 3R section using the optical node device 13 as the 3R destinationnode.

The optical path setting unit 22 which receives this recognition resultgenerates DITR=11 as a message showing that the optical node device 11itself is the 3R source node, and DETR=13 as a message showing that theoptical node device 13 is the 3R destination node.

The optical path setting unit 22 of the optical node device 11 ensuresthe resources for optical path setting and the 3R relay, and loadsDITR=11 and DETR=13 when sending the optical path setting request (Path)to the optical node device 12.

The 3R relay implementation determining unit 21 of the optical nodedevice 12 which receives the optical path setting request (Path) fromthe optical node device 11 refers to the DITR=11 and DETR=13 torecognize that the optical node device 12 itself is not the optical nodedevice for implementing the 3R relay. The optical path setting unit 22of the optical node device 12 ensures the resources for optical pathsetting, and loads the intact DITR=11 and DETR=13 from the optical nodedevice 11 when sending the optical path setting request (Path) to theoptical node device 13.

The 3R relay implementation determining unit 21 of the optical nodedevice 13 which receives the optical path setting request (Path) fromthe optical node device 12 refers to the DITR=11 and DETR=13.Furthermore, the 3R section information storing unit 20 stores the 3Rsection information shown in FIG. 25 since the optical node device 13 isthe 3R source node, and thus the 3R relay implementation determiningunit 21 refers to this 3R section information. Therefore, the 3R relayimplementation determining unit 21 recognizes that the optical nodedevice 13 itself is the 3R destination node and the 3R source node ofthe 3R section using the optical node device 14 as the 3R destinationnode.

The optical path setting unit 22 which receives this recognition resultgenerates DITR=13 as a message showing that the optical node device 13itself is the 3R source node, and DETR=14 as a message showing that theoptical node device 14 is the 3R destination node.

The optical path setting unit 22 of the optical node device 13 ensuresthe resources for optical path setting and the 3R relay, and loadsDITR=13 and DETR=14 when sending the optical path setting request (Path)to the optical node device 14.

The 3R relay implementation determining unit 21 of the optical nodedevice 14 which receives the optical path setting request (Path) fromthe optical node device 13 refers to the DITR=13 and DETR=14 torecognize that the optical node device 14 itself is the 3R destinationnode. Furthermore, the 3R relay implementation determining unit 21 makesa determination based on the determination policy of “when the opticalnode device itself is the optical node device corresponding to the 3Rdestination node on the optical path and is not a destination node, theoptical node device requests the next-hop optical node device toimplement the 3R relay using the optical node device itself as the 3Rsource node and the next-hop optical node device as the 3R destinationnode”, and determines that it is not required to implement the 3R relaysince the optical node device 14 itself is the destination node.

The optical path setting unit 22 of the optical node device 14 ensuresthe resources for optical path setting and sends the optical pathsetting completion notification (Resv) to the optical node device 13.The optical path setting completion notification (Resv) is transmittedthrough the optical node devices 13->12->11>10->1 so that the opticalpath setting is completed.

Sixth Embodiment

Optical node devices according to a sixth embodiment are described withreference to FIG. 4, FIG. 14, FIG. 15, and FIG. 27 to FIG. 36. FIG. 27to FIG. 30 and FIG. 32 to FIG. 35 show 3R section information of anoptical node device according to the sixth embodiment. FIG. 31 and FIG.36 show signaling procedures when setting an optical path in the sixthembodiment.

As shown in FIG. 4, the optical node device according to the sixthembodiment comprises: a 3R section information storing unit 20 whichstores 3R section information using the optical node device itself asthe 3R source node and the 3R destination node; and an optical pathsetting unit 22 which receives a message included in an optical pathsetting request showing that the optical node device itself is the 3Rdestination node on the downstream optical path, then refers to the 3Rsection information storing unit 20 when the optical node device itselfis not the destination node, and if the optical node device itself isthe 3R source node on the downstream optical path, determines that theoptical node device itself is the optical node device for implementingthe 3R relay, and sends a message to transmit to the optical node devicecorresponding to the 3R destination node of the 3R section on thedownstream optical path using the optical node device itself as the 3Rsource node, that the optical node device corresponding to the 3Rdestination node is the 3R destination node.

Moreover, the optical path setting unit 22 receives a message includedin an optical path setting request showing that the optical node deviceitself is the 3R source node on the upstream optical path, anddetermines that the optical node device itself is the optical nodedevice for implementing the 3R relay on the upstream optical path, thenrefers to the 3R section information storing unit 20 when the opticalnode device itself is not the destination node, and when the opticalnode device itself is the 3R destination node on this upstream opticalpath, sends a message to transmit to the optical node devicecorresponding to the 3R source node on the upstream optical path usingthe optical node device itself as the 3R destination node, that theoptical node device corresponding to the 3R source node is the 3R sourcenode.

Furthermore, the optical path setting unit 22 receives a messageincluded in an optical path setting request showing that the opticalnode device itself is the 3R destination node on the downstream opticalpath, then refers to the 3R section information storing unit 20 when theoptical node device itself is not the destination node, determines whenthe optical node device itself is not the 3R source node on thedownstream optical path, that the optical node device itself is theoptical node device for implementing the 3R relay using the optical nodedevice itself as the 3R source node and the next-hop optical node deviceon the downstream optical path as the 3R destination node, and generatesa message to transmit to this next-hop optical node device, that thisnext-hop optical node device is the 3R destination node of the opticalnode device itself.

Moreover, the optical path setting unit 22 receives a message includedin an optical path setting request showing that the optical node deviceitself is the 3R source node on the upstream optical path, anddetermines that the optical node device itself is the optical nodedevice for implementing the 3R relay on the upstream optical path, thenrefers to the 3R section information storing unit 20 when the opticalnode device itself is not the destination node, and generates a messagewhen the optical node device itself is not the 3R destination node onthe upstream optical path, to transmit to the previous-hop optical nodedevice, that this previous-hop optical node device on the upstreamoptical path is the 3R source node using the optical node device itselfas the 3R destination node.

In the sixth embodiment, the optical node device corresponding to the 3Rsource node or the 3R destination node stores the 3R section informationrelating to the optical node device itself. Since it does not store theother 3R section information, the information storage resources can beeffectively used.

Next is a description of the operation of the optical node deviceaccording to the sixth embodiment. Here as shown in FIG. 15, is adescription of an example where a bi-directional optical path from theoptical node device 1 to the optical node device 14 (double lines) isset. The 3R relay implementation determining unit 21 of the optical nodedevice 1 recognizes that a bi-directional optical path setting requestusing the optical node device 1 as the source node has issued, anddetermines that the optical node device 1 implements the 3R relay on thedownstream optical path. Moreover, the 3R section information storingunit 20 stores the 3R section information shown in FIG. 27, so that the3R relay implementation determining unit 21 recognizes that the 3Rdestination node if using the optical node device 1 as the 3R sourcenode, is the optical node device 4 on the downstream optical path.Moreover, the 3R relay implementation determining unit 21 recognizesthat the optical node device 1 is the 3R destination node if using theoptical node device 4 as the 3R source node on the upstream opticalpath.

The optical path setting unit 22 of the optical node device 1 receivesthe determination of the 3R relay implementation determining unit 21 andensures the resources for the downstream optical path setting. Then, asshown in FIG. 31, the optical path setting unit 22 loads a message ofDITR=1 and DETR=4 showing that the optical node device 1 is the 3Rsource node on the downstream optical path and that the 3R destinationnode of this 3R section is the optical node device 4, into the opticalpath setting request (Path) when sending the optical path settingrequest (Path) to the optical node device 2.

Furthermore, the 3R relay implementation determining unit 21 refers tothe 3R section information storing unit 20 to recognize that the opticalnode device 1 is the 3R destination node of the upstream optical path tobe set, and determines that the optical node device 1 does not implementthe 3R relay on the upstream optical path. The optical path setting unit22 of the optical node device 1 receives the determination of the 3Rrelay implementation determining unit 21 and ensures the resources forthe upstream optical path setting. Then, as shown in FIG. 31, theoptical path setting unit 22 loads a message of UETR=1 and UITR=4showing that the optical node device 1 is the 3R destination node on theupstream optical path and that the 3R source node of this 3R section isthe optical node device 4, into the optical path setting request whensending the optical path setting request (Path) to the optical nodedevice 2.

The optical path setting unit 22 of the optical node device 2 whichreceives the optical path setting request (Path) from the optical nodedevice 1 queries the 3R relay implementation determining unit 21 as towhether or not the optical node device 2 is the optical node device forimplementing the 3R relay on the upstream or downstream optical path.Since the optical node device 2 is neither the 3R source node nor the 3Rdestination node, the 3R section information storing unit 20 does notstore the 3R section information. Therefore, it is determined that theoptical node device 2 does not implement the 3R relay.

The optical path setting unit 22 of the optical node device 2 receivesthe determination of the 3R relay implementation determining unit 21 andensures the resources for upstream and downstream optical path setting.Then, as shown in FIG. 31, since the optical node device 2 does notimplement the 3R relay, when sending the optical path setting request(Path) to the optical node device 3, the optical path setting unit 22loads the intact DITR=1, DETR=4, UETR=1 and UITR=4 from the optical nodedevice 1 into the optical path setting request.

The optical path setting unit 22 of the optical node device 3 whichreceives the optical path setting request (Path) from the optical nodedevice 2 queries the 3R relay implementation determining unit 21 as towhether or not the optical node device 3 is the optical node device forimplementing the 3R relay. The 3R relay implementation determining unit21 of the optical node device 3 refers to the 3R section informationstored in the 3R section information storing unit 20 shown in FIG. 28,and recognizes that the optical node device 3 may implement the 3R relaysince the optical node device 3 is the 3R source node on the 3R sectionfrom the optical node device 3 to the optical node device 14 on thedownstream optical path, and that the optical node device 3 may notimplement the 3R relay but transmit the intact optical signal to theoptical node device 4 being the 3R destination node since, due to theDITR=1 and DETR=4, there is the 3R section from the optical node device1 to the optical node device 4 on the downstream optical path, and theoptical node device 3 is not the 3R source node on this 3R section.

In such a case, the 3R relay implementation determining unit 21 of theoptical node device 3 uses a 3R implementation simulating unit 23 and acomparison unit 24 to compare the number of 3R implementations in thecase where the optical node device 3 functions as the 3R source node,and the case where it does not function as the 3R source node, withregards to the downstream optical path from the optical node device 3 tothe optical node device 14. The description hereunder is similar to thatof the first embodiment.

Such simulation results of the 3R implementation simulating unit 23 areinput into the comparison unit 24. In the comparison unit 24, it isfound that the number of 3R implementations can be reduced in the casewhere the optical node device 3 implements the 3R relay on thedownstream optical path compared to the case where the optical nodedevice 3 does not implement the 3R relay. Therefore to that effect isoutput as a comparison result. As a comparison result, the 3R relayimplementation determining unit 21 selects the case having the lowernumber of 3R implementations. Therefore, it is determined that theoptical node device 3 implements the 3R relay on the downstream opticalpath.

Furthermore, the 3R relay implementation determining unit 21 finds outthat the optical node device 3 is not the 3R source node on the upstreamoptical path, and due to the delivery of the UETR=1 and UITR=4 from theoptical node device 2, that there is a 3R section using the optical nodedevice 1 as the 3R destination node and the optical node device 4 as the3R source node, so that the 3R relay implementation determining unit 21determines not to implement the 3R relay on the upstream optical path.

The optical path setting unit 22 of the optical node device 3 receivesthe determination of the 3R relay implementation determining unit 21 andensures the resources for optical path setting and the 3R relay. Then,as shown in FIG. 31, the optical path setting unit 22 loads a message ofDITR=3 and DETR=14 showing that the optical node device 3 is the 3Rsource node on the downstream optical path and that the 3R destinationnode of this 3R section is the optical node device 14, into the opticalpath setting request when sending the optical path setting request(Path) to the optical node device 4. Moreover, since the optical nodedevice 3 does not implement the 3R relay on the upstream optical path,the optical path setting unit 22 loads the intact UETR=1 and UITR=4delivered from the optical node device 2 into the optical path settingrequest.

The optical path setting unit 22 of the optical node device 4 whichreceives the optical path setting request (Path) from the optical nodedevice 3 queries the 3R relay implementation determining unit 21 as towhether or not the optical node device 4 is the optical node device forimplementing the 3R relay. The 3R relay implementation determining unit21 of the optical node device 4 refers to the 3R section informationshown in FIG. 29 and stored in the 3R section information storing unit20 and finds out that the optical node device 4 is the 3R destinationnode on the downstream optical path, and due to the delivery of theDITR=3 and DETR=14 from the optical node device 3, that the 3R sectionis up to the optical node device 14 if the optical node device 3 is the3R source node on the downstream optical path, so that the 3R relayimplementation determining unit 21 determines that the optical nodedevice 4 is not required to implement the 3R relay.

Furthermore, the 3R relay implementation determining unit 21 refers tothe 3R section information stored in the 3R section information storingunit 20 and finds out due to the delivery of the UETR=1 and UITR=4 fromthe optical node device 3, that the optical node device 4 is the 3Rsource node on the upstream optical path using the optical node device 1as the 3R destination node, so that the 3R relay implementationdetermining unit 21 determines to implement the 3R relay on the upstreamoptical path.

The optical path setting unit 22 of the optical node device 4 receivesthe determination of the 3R relay implementation determining unit 21 andensures the resources for optical path setting and 3R relay. Then, asshown in FIG. 31, since the optical node device 4 does not implement the3R relay on the downstream optical path, when sending the optical pathsetting request (Path) to the optical node device 5, the optical pathsetting unit 22 loads the intact DITR=3 and DETR=14 from the opticalnode device 3 into the optical path setting request.

Moreover, the optical node device 4 recognizes that the optical nodedevice 4 is the 3R source node on the upstream optical path, and withreference to the 3R section information storing unit 20 that the opticalnode device 4 itself is not the 3R destination node on this upstreamoptical path. In such a case, the previous-hop optical node device 5 onthe upstream optical path is required to be the 3R source node using theoptical node device 4 itself as the 3R destination node. Therefore, inorder to transmit this to the optical node device 5, UETR=4 and UITR=5are loaded into the optical path setting request.

The optical path setting unit 22 of the optical node device 5 whichreceives the optical path setting request (Path) from the optical nodedevice 4 queries the 3R relay implementation determining unit 21 as towhether or not the optical node device 5 is the optical node device forimplementing the 3R relay. The 3R relay implementation determining unit21 of the optical node device 5 refers to the 3R section informationshown in FIG. 30 and stored in the 3R section information storing unit20 and finds out that the optical node device 5 is not the 3R sourcenode on the downstream optical path, and due to the delivery of theDITR=3 and DETR=14 from the optical node device 4, that the 3R sectionis up to the optical node device 14 if the optical node device 3 is the3R source node, so that the 3R relay implementation determining unit 21determines that the optical node device 5 does not implement the 3Rrelay. Moreover, due to the delivery of the UETR=4 and UITR=5 from theoptical node device 4, the 3R relay implementation determining unit 21refers to the 3R section information storing unit 20 to recognize thatthe optical node device 5 is the 3R source node on the upstream opticalpath, so that the 3R relay implementation determining unit 21 determinesto implement the 3R relay on the upstream optical path.

The optical path setting unit 22 of the optical node device 5 receivesthe determination of the 3R relay implementation determining unit 21 andensures the resources for optical path setting and 3R relay. Then, asshown in FIG. 31, since the optical node device 5 does not implement the3R relay on the downstream optical path, when sending the optical pathsetting request (Path) to the optical node device 14, the optical pathsetting unit 22 loads the intact DITR=3 and DETR=14 from the opticalnode device 4 into the optical path setting request.

Moreover, the optical node device 5 is the 3R source node on theupstream optical path; however the 3R section using the optical nodedevice 14 as the 3R source node and the optical node device 5 as the 3Rdestination node is not set. In such a case, the optical node device 14is required to be the 3R source node based on the determination policyof “when the optical node device itself does not belong to any 3Rsection having the 3R source node on the optical path passing throughthe optical node device itself, it is determined that the optical nodedevice itself is the optical node device for implementing the 3R relayusing the optical node device itself as the 3R source node and thenext-hop optical node device as the 3R destination node.” Therefore,UETR=5 and UITR=14 showing that the optical node device 5 is the 3Rdestination node and the 3R source node of this 3R section is theoptical node device 14, are loaded into the optical path request.

The optical path setting unit 22 of the optical node device 14 whichreceives the optical path setting request (Path) from the optical nodedevice 5 queries the 3R relay implementation determining unit 21 as towhether or not the optical node device 14 is the optical node device forimplementing the 3R relay. The 3R relay implementation determining unit21 of the optical node device 14 refers to the 3R section informationshown in FIG. 35 and stored in the 3R section information storing unit20 and determines that it is not required to implement the 3R relay onthe downstream optical path since the optical node device 14 is thedestination node, but due to the delivery of the UETR=5 and UITR=14 fromthe optical node device 5 it is required to implement the 3R relay onthe upstream optical path using the optical node device 14 as the 3Rsource node and the optical node device 5 as the 3R destination node.

The optical path setting unit 22 of the optical node device 14 receivesthe determination of the 3R relay implementation determining unit 21 andensures the resources for optical path setting and 3R relay. Then, asshown in FIG. 31, the optical path setting unit 22 sends the opticalpath setting completion notification (Resv) to the optical node device5.

This optical path setting completion notification (Resv) is transmittedthrough the optical node devices 5->4->3->2->1 so that the optical pathsetting is completed. In this way, the respective optical node devices1, 2, 3, 4, 5, and 14 can determine autonomously whether or not theythemselves implement the 3R relay in the process of performing thesignaling procedure of the optical path setting.

Next is a description of another example of the operation of the opticalnode device according to the sixth embodiment. Here as shown in FIG. 18,is a description of an example where a bi-directional optical path fromthe optical node device 1 to the optical node device 14 (double lines)is set. The 3R relay implementation determining unit 21 of the opticalnode device 1 recognizes that a bi-directional optical path settingrequest using the optical node device 1 as the source node has issued,and determines that the optical node device 1 implements the 3R relay onthe downstream optical path. Moreover, the 3R section informationstoring unit 20 stores the 3R section information shown in FIG. 27, sothat the 3R relay implementation determining unit 21 recognizes that the3R destination node if using the optical node device 1 as the 3R sourcenode, is the optical node device 11 on the downstream optical path.Moreover, the 3R relay implementation determining unit 21 recognizesthat the optical node device 1 is the 3R destination node on theupstream optical path if using the optical node device 12 as the 3Rsource node.

The optical path setting unit 22 of the optical node device 1 receivesthe determination of the 3R relay implementation determining unit 21 andensures the resources for the downstream optical path setting. Then, asshown in FIG. 36, the optical path setting unit 22 loads a message ofDITR=1 and DETR=11 showing that the optical node device 1 is the 3Rsource node on the downstream optical path and that the 3R destinationnode of this 3R section is the optical node device 11, into the opticalpath setting request (Path) when sending the optical path settingrequest (Path) to the optical node device 10.

Furthermore, the 3R relay implementation determining unit 21 refers tothe 3R section information storing unit 20 to recognize that the opticalnode device 1 is the 3R destination node of the upstream optical path tobe set, and determines that the optical node device 1 does not implementthe 3R relay on the upstream optical path.

The optical path setting unit 22 of the optical node device 1 receivesthe determination of the 3R relay implementation determining unit 21 andensures the resources for the upstream optical path setting and the 3Rrelay. Then, as shown in FIG. 36, the optical path setting unit 22 loadsa message of UETR=1 and UITR=12 showing that the optical node device 1is the 3R destination node on the upstream optical path and that the 3Rsource node of this 3R section is the optical node device 12, into theoptical path setting request when sending the optical path settingrequest (Path) to the optical node device 10.

The optical path setting unit 22 of the optical node device 10 whichreceives the optical path setting request (Path) from the optical nodedevice 1 queries the 3R relay implementation determining unit 21 as towhether or not the optical node device 10 is the optical node device forimplementing the 3R relay on the upstream or downstream optical path.The optical node device 10 is neither the 3R source node nor the 3Rdestination node, and does not store the 3R section information in the3R section information storing unit 20. Therefore, it is determined thatthe optical node device 10 does not implement the 3R relay on anyupstream or downstream optical paths.

The optical path setting unit 22 of the optical node device 10 receivesthe determination of the 3R relay implementation determining unit 21 andensures the resources for upstream and downstream optical path setting.Then, as shown in FIG. 36, since the optical node device 10 does notimplement the 3R relay, when sending the optical path setting request(Path) to the optical node device 11, the optical path setting unit 22loads the intact DITR=1, DETR=11, UETR=1 and UITR=12 from the opticalnode device 1 into the optical path setting request.

The optical path setting unit 22 of the optical node device 11 whichreceives the optical path setting request (Path) from the optical nodedevice 10 queries the 3R relay implementation determining unit 21 as towhether or not the optical node device 11 is the optical node device forimplementing the 3R relay. The 3R relay implementation determining unit21 of the optical node device 11 refers to the 3R section informationshown in FIG. 32 and stored in the 3R section information storing unit20, and determines that the optical node device 11 implements the 3Rrelay since the optical node device 11 is the 3R source node on the 3Rsection from the optical node device 11 to the optical node device 13 onthe downstream optical path.

Furthermore, the 3R relay implementation determining unit 21 finds outthat the optical node device 11 is not the 3R source node on theupstream optical path, and due to the delivery of the UETR=1 and UITR=12from the optical node device 10, that the optical node device 12 is the3R source node if the optical node device 1 is used as the 3Rdestination node, so that it determines not to implement the 3R relay onthe upstream optical path.

The optical path setting unit 22 of the optical node device 11 receivesthe determination of the 3R relay implementation determining unit 21 andensures the resources for optical path setting and the 3R relay. Then,as shown in FIG. 36, the optical path setting unit 22 loads a message ofDITR=11 and DETR=13 showing that the optical node device 11 is the 3Rsource node on the downstream optical path and that the 3R destinationnode of this 3R section is the optical node device 13, into the opticalpath setting request when sending the optical path setting request(Path) to the optical node device 12. Moreover, since the optical nodedevice 11 does not implement the 3R relay on the upstream optical path,the optical path setting unit 22 loads the intact UETR=1 and UITR=12delivered from the optical node device 10 into the optical path settingrequest.

The optical path setting unit 22 of the optical node device 12 whichreceives the optical path setting request (Path) from the optical nodedevice 11 queries the 3R relay implementation determining unit 21 as towhether or not the optical node device 12 is the optical node device forimplementing the 3R relay. The 3R relay implementation determining unit21 of the optical node device 12 refers to the 3R section informationshown in FIG. 33 and stored in the 3R section information storing unit20 and determines that the optical node device 12 is neither the 3Rsource node nor the 3R destination node on the downstream optical pathand it is not required to implement the 3R relay.

Furthermore, the 3R relay implementation determining unit 21 refers tothe 3R section information stored in the 3R section information storingunit 20 and finds out due to the delivery of the UETR=1 and UITR=12 fromthe optical node device 11 that the optical node device 12 is the 3Rsource node on the upstream optical path using the optical node device 1as the 3R destination node, so that the 3R relay implementationdetermining unit 21 determines to implement the 3R relay on the upstreamoptical path.

The optical path setting unit 22 of the optical node device 12 receivesthe determination of the 3R relay implementation determining unit 21 andensures the resources for optical path setting and 3R relay. Then, asshown in FIG. 36, since the optical node device 12 does not implementthe 3R relay on the downstream optical path, when sending the opticalpath setting request (Path) to the optical node device 13, the opticalpath setting unit 22 loads the intact DITR=1 and DETR=13 from theoptical node device 11 into the optical path setting request.

Moreover, the optical node device 12 is the 3R source node on theupstream optical path and is the 3R destination node if using theoptical node device 14 as the 3R source node of the upstream opticalpath. Therefore, the UETR=12 and UITR=14 are loaded into the opticalpath setting request.

The optical path setting unit 22 of the optical node device 13 whichreceives the optical path setting request (Path) from the optical nodedevice 12 queries the 3R relay implementation determining unit 21 as towhether or not the optical node device 13 is the optical node device forimplementing the 3R relay. The 3R relay implementation determining unit21 of the optical node device 13 refers to the 3R section informationshown in FIG. 34 and stored in the 3R section information storing unit20, and finds out due to the delivery of the DITR=11 and DETR=13 fromthe optical node device 12 that the optical node device 13 is the 3Rdestination node on the downstream optical path.

Here, a determination is made based on the determination policy of “inresponse to a message included in the optical path setting requestshowing that the optical node device itself is the 3R destination nodeon the downstream optical path, it refers to the 3R section informationstoring unit 20 when the optical node device itself is not thedestination node, and it is determined when the optical node deviceitself is not the 3R source node on the downstream optical path, thatthe optical node device itself is the optical node device forimplementing the 3R relay using the optical node device itself as the 3Rsource node and the next-hop optical node device as the 3R destinationnode on the downstream optical path”, and it is determined that theoptical node device 13 implements the 3R relay. Moreover, in this case,the optical path setting unit 22 generates DETR=14 as a message totransmit to the next-hop optical node device 14, that this optical nodedevice 14 is the 3R destination node of the optical node device 13.Moreover, the optical path setting unit 22 determines that on theupstream optical path, the optical node device 13 is neither the 3Rsource node nor the 3R destination node and does not implement the 3Rrelay.

The optical path setting unit 22 of the optical node device 13 receivesthe determination of the 3R relay implementation determining unit 21 andensures the resources for optical path setting and 3R relay. Then, asshown in FIG. 36, when sending the optical path setting request (Path)to the optical node device 14, the optical path setting unit 22 loads amessage of DITR=13 and DETR=14 showing that the optical node device 13is the 3R source node on the downstream optical path and the 3Rdestination node of this 3R section is the optical node device 14, intothe optical path setting request. Moreover, since the optical nodedevice 13 does not implement the 3R relay on the upstream optical path,the optical path setting unit 22 loads the intact UETR=12 and UITR=14from the optical node device 12 into the optical path setting request.

The optical path setting unit 22 of the optical node device 14 whichreceives the optical path setting request (Path) from the optical nodedevice 13 queries the 3R relay implementation determining unit 21 as towhether or not the optical node device 14 is the optical node device forimplementing the 3R relay. The 3R relay implementation determining unit21 of the optical node device 14 refers to the 3R section informationshown in FIG. 35 and stored in the 3R section information storing unit20 and determines that it is not required to implement the 3R relay onthe downstream optical path since the optical node device 14 is thedestination node, but due to the delivery of the UETR=12 and DITR=14from the optical node device 13, it is required to implement the 3Rrelay on the upstream optical path using the optical node device 14 asthe 3R source node and the optical node device 12 as the 3R destinationnode.

The optical path setting unit 22 of the optical node device 14 receivesthe determination of the 3R relay implementation determining unit 21 andensures the resources for optical path setting and 3R relay. Then, asshown in FIG. 36, the optical path setting unit 22 sends the opticalpath setting completion notification (Resv) to the optical node device13.

This optical path setting completion notification (Resv) is transmittedthrough the optical node devices 13->12->11->10->1 so that the opticalpath setting is completed. In this way, the respective optical nodedevices 1, 10, 11, 12, 13, and 14 can determine autonomously whether ornot they themselves implement the 3R relay in the process of performingthe signaling procedure of the optical path setting.

Seventh Embodiment

A network control device and optical node devices according to a seventhembodiment are described with reference to FIG. 37 to FIG. 40. FIG. 37is a conceptual diagram showing the relationship of the network controldevice and the optical node devices according to the seventh embodiment.FIG. 38 is a block diagram of the network control device according tothe seventh embodiment. FIG. 39 is a schematic block diagram of theoptical node device according to the seventh embodiment. FIG. 40 is asequence diagram showing the operation of the seventh embodiment.

As shown in FIG. 37, the network control device 40 according to theseventh embodiment has a function for mutually communicating with anyrespective optical node devices 1 to 14, and integrally manages anoptical network 50. Hereunder is a description of the managing functionconcerned with the 3R section information, among the managing functionsof the network control device 40.

That is, as shown in FIG. 38, the network control device 40 according tothe seventh embodiment comprises: a 3R section information database 41which stores the 3R section information corresponding to the topologyinformation of the optical network 50; and a 3R section informationproviding unit 43 which provides the optical node device with the 3Rsection information stored in this 3R section information database 41according to a request from the optical node device.

Moreover, the 3R section information stored in the 3R sectioninformation database 41 is the 3R section information collected by a 3Rsection information collection unit 42. As the 3R section information ofthe optical network 50 is updated, the 3R section information collectionunit 42 updates the 3R section information stored in the 3R sectioninformation database 41.

As shown in FIG. 39, the optical node device according to the seventhembodiment comprises a 3R section information request unit 27 whichrequests the network control device 40 that manages the optical network50 to which the optical node device itself belongs, to provide the 3Rsection information corresponding to the topology information of thisoptical network 50 and obtains this information.

Next is a description of the operation of the seventh embodiment withreference to FIG. 40. The 3R section information request unit 27 of theoptical node device requests the 3R section information required by theoptical node device itself from the 3R section information providingunit 43 of the network control device 40 (Step 1). Here, the 3R sectioninformation required by the optical node device itself variously means:the 3R section information of the whole optical network 50; the 3Rsection information on the optical path passing through the optical nodedevice itself; the 3R section information on the optical path where theoptical node device itself becomes the source node; the 3R sectioninformation on the 3R section where the optical node device itselfbecomes the 3R source node; or the 3R section information on the 3Rsection where the optical node device itself becomes the 3R source nodeor the 3R destination node. The 3R section information request unit 27recognizes the 3R section information required by the optical nodedevice itself and requests it from the 3R section information providingunit 43 of the network control device 40. The 3R section informationproviding unit 43 of the network control device 40 searches for thenecessary information requested (Step 2).

The 3R section information providing unit 43 extracts the necessaryinformation of the 3R section information from the 3R sectioninformation database 41 (Step 3), and transfers it to the 3R sectioninformation request unit 27 of the optical node device (Step 4). The 3Rsection information request unit 27 examines the 3R section informationtransferred from the network control device 40 and stores it into the 3Rsection information storing unit 20 if it is definitely the necessaryinformation requested (Step 5).

In the process of the seventh embodiment, the processing load requiredfor searching and extracting the necessary information by the 3R sectioninformation providing unit 43 of the network control device 40, is thehighest.

Eighth Embodiment

A network control device and optical node devices according to an eighthembodiment are described with reference to FIG. 37, FIG. 38, FIG. 41,and FIG. 42. FIG. 37 is a conceptual diagram showing the relationship ofthe network control device and the optical node devices according to theeighth embodiment used in common with the seventh embodiment. FIG. 38 isa block diagram of the network control device according to the eighthembodiment used in common with the seventh embodiment. FIG. 41 is aschematic block diagram of the optical node device according to theeighth embodiment. FIG. 42 is a sequence diagram showing the operationof the eighth embodiment.

As shown in FIG. 37, the network control device 40 according to theeighth embodiment has a function for mutually communicating with anyrespective optical node devices 1 to 14, and integrally manages anoptical network 50. Hereunder is a description of the managing functionconcerned with the 3R section information, among the managing functionsof the network control device 40.

That is, as shown in FIG. 38, the network control device 40 according tothe eighth embodiment comprises: a 3R section information database 41which stores the 3R section information corresponding to the topologyinformation of the optical network 50; and a 3R section informationproviding unit 43 which provides the optical node device with the 3Rsection information stored in this 3R section information database 41according to a request from the optical node device.

Moreover, the 3R section information stored in the 3R sectioninformation database 41 is the 3R section information collected by a 3Rsection information collection unit 42. As the 3R section information ofthe optical network 50 is updated, the 3R section information collectionunit 42 updates the 3R section information stored in the 3R sectioninformation database 41.

As shown in FIG. 41, the optical node device according to the eighthembodiment comprises: a 3R section information request unit 27 whichrequests the network control device 40 that manages the optical network50 to which the optical node device itself belongs, to provide the 3Rsection information corresponding to the topology information of thisoptical network 50 and obtains this information; and an informationselecting unit 30 for selecting at least a part of the informationrelated to the optical node device itself, among the obtained 3R sectioninformation and storing this information.

Next is a description of the operation of the eighth embodiment withreference to FIG. 42. The 3R section information request unit 27 of theoptical node device requests the 3R section information from the 3Rsection information providing unit 43 of the network control device 40(Step 11). At this time, in the eighth embodiment, the necessaryinformation of the optical node device itself is not specified.

The 3R section information providing unit 43 of the network controldevice 40 transfers the intact request to the 3R section informationdatabase 41 (Step 12). The 3R section information providing unit 43extracts the 3R section information from the 3R section informationdatabase 41 (Step 13), and transfers it to the information selectingunit 30 of the optical node device (Step 14). The information selectingunit 30 selects the information required by the optical node deviceitself among the 3R section information transferred from the networkcontrol device 40, and discards the unnecessary information (Step 15).The necessary information generated in this way is stored in the 3Rsection information storing unit 20 (Step 16).

Compared to the seventh embodiment, the information selecting unit 30 isadded to the block construction of the optical node device in the eighthembodiment. However, due to the 3R section information request unit 27of the optical node device, and the 3R section information providingunit 43 of the network control device 40, it is not required to selectthe necessary information, and the processing load can be reducedcompared to the seventh embodiment.

Ninth Embodiment

An optical node device according to a ninth embodiment is described withreference to FIG. 43. FIG. 43 is a schematic block diagram of theoptical node device according to the ninth embodiment. As shown in FIG.43, the optical node device according to the ninth embodiment comprises:a 3R section information request unit 27 which requests and obtains the3R section information corresponding to the topology information of theoptical network 50 to which the optical node device itself belongs, fromthe network control device 40 that manages the optical network 50 towhich the optical node device itself belongs; a 3R section informationstoring unit 20 which stores the 3R section information obtained by this3R section information request unit 27; and an advertising unit 28 whichadvertises the 3R section information stored in this 3R sectioninformation storing unit 20 to another optical node device.

For example, in the case where all the optical node devices store thecommon 3R section information, any of the optical node devices 1 to 14obtains the 3R section information from the network control device 40and advertises it to the other optical node devices using theadvertising unit 28, so that the processing load of the network controldevice 40 can be decreased. Alternatively, two optical node devices ormore obtain the 3R section information respectively from the networkcontrol device 40 and advertise this to the other optical node devices,so that even if the 3R section information obtained by any of theoptical node devices is in short, the shortage can be mutuallycompensated and highly reliable 3R section information can be stored.

Tenth Embodiment

An optical node device according to a tenth embodiment is described withreference to FIG. 44. FIG. 44 is a schematic block diagram of theoptical node device according to the tenth embodiment. As shown in FIG.44, the optical node device according to the tenth embodiment comprises:a 3R section information request unit 27 which requests and obtains the3R section information corresponding to the topology information of theoptical network 50 to which the optical node device itself belongs, fromthe network control device 40 that manages the optical network 50 towhich the optical node device itself belongs when the optical nodedevice itself is the source node; a 3R section information storing unit20 which stores the 3R section information obtained by this 3R sectioninformation request unit 27; and a transmission unit 29 which transmitsthe 3R section information stored in this 3R section information storingunit 20 to another optical node device included in the optical path upto the destination node when the optical node device itself is thesource node.

For example, it is used in the case where the optical node device beingthe source node of the optical path, transmits the 3R sectioninformation to another optical node device included in the route of theoptical path, from the optical node device itself to the optical nodedevice being the destination node. Compared to the ninth embodimentwhere the 3R section information is advertised to an unspecifieddestination, the 3R section information is transmitted to a specificdestination in the tenth embodiment.

Eleventh Embodiment

An optical node device according to an eleventh embodiment is describedwith reference to FIG. 45. FIG. 45 is a schematic block diagram of theoptical node device according to the eleventh embodiment. As shown inFIG. 45, the optical node device according to the eleventh embodimentcomprises: a 3R section information request unit 27 which requests andobtains the 3R section information corresponding to the topologyinformation of the optical network 50 to which the optical node deviceitself belongs, from the network control device 40 that manages theoptical network 50 to which the optical node device itself belongs whenthe optical node device itself is the source node; a 3R sectioninformation storing unit 20 which stores the 3R section informationobtained by this 3R section information request unit 27; an advertisingunit 28 which advertises the 3R section information stored in this 3Rsection information storing unit 20 to another optical node device; andan information selecting unit 30 which determines whether or not theadvertisement by the advertising unit 28 is related to the optical pathpassing through the optical node device itself, and this informationselecting unit 30 discard the advertisement if the advertisement is notrelated to the optical path passing through the optical node deviceitself, and stores the contents of the advertisement into the 3R sectioninformation storing unit 20 if the advertisement is related to theoptical path passing through the optical node device itself.

In the tenth embodiment, the transmission unit 29 is required totransmit the 3R section information to the specific destination.However, in the eleventh embodiment, it is sufficient that theadvertising unit 30 advertises the 3R section information to anunspecified destination, so that the processing load for destinationcontrol can be omitted. Furthermore, the 3R section information notrelated to the optical node device itself can be discarded using theinformation selecting unit 30. Therefore the information storageresources of the 3R section information storing unit 20 can beeffectively used.

Twelfth Embodiment

An optical node device according to a twelfth embodiment is describedwith reference to FIG. 4 and FIG. 46. FIG. 4 is a schematic blockdiagram of the optical node device according to the twelfth embodimentused in common with the first embodiment. FIG. 46 is an explanatorydiagram of a 3R relay implementation node determination method of thetwelfth embodiment. As shown in FIG. 4, the optical node deviceaccording to the twelfth embodiment comprises: a 3R section informationstoring unit 20 which stores the information on the number of hopsbetween the optical node device itself and the 3R destination node inthe 3R section to which the optical node device itself belongs; and a 3Rrelay implementation determining unit 21 which determines autonomouslywhether or not the optical node device itself implements the 3R relaywith respect to the optical signal transmitted from the 3R source nodein the 3R section to which the optical node device itself belongs. This3R relay implementation determining unit 21 determines to implement the3R relay if T>TH_T and H<TH_H assuming that the number of 3R trunksprovided by the optical node device itself is T, the threshold of thenumber of vacant 3R trunks is TH_T, and the threshold of the number ofhops up to the 3R destination node is TH_H.

As shown in FIG. 46, if the optical node device 1 is the 3R source node,the optical node device 3 is the 3R destination node, and the opticalnode device 2 is between the optical node devices 1 and 3, then, theoptical node device 2 is the optical node device where “the one opticalnode device is the 3R source node on any one of a plurality of 3Rsections including the overlapped part on the optical path passingthrough this one optical node device, and it does not correspond to the3R source node or 3R destination node on any other 3R sections”.

In such a case, in the embodiments prior to the twelfth embodiment, the3R relay implementation determining unit 21 was described as a unitwhich uses the 3R implementation simulating unit 23 and the comparisonunit 24 “to refer to the 3R section information on the optical path fromthe one optical node device to the destination node, to compare thenumber of 3R implementations in the case where the one optical nodedevice functions as the 3R source node, and the case where the oneoptical node does not function as the 3R source node, and to determinebased on this comparison result that the one optical node device is theoptical node device for implementing 3R relay when the number of 3Rimplementations in the case where the one optical node device functionsas the 3R source node, is lower than that in the case where the opticalnode device does not function as the 3R source node.”

On the other hand, in the twelfth embodiment, whether the 3R relay isimplemented or not is determined by a simpler method than thesimulation. That is, it determines to implement the 3R relay if T>TH_Tand H<TH_H.

That is, in the optical node device on the route of a certain opticalpath, in the case where this optical node device is the 3R source nodeon any 3R section and has a 3R trunk, if the number of the 3R trunks ofthis optical node device has enough room, and furthermore the number ofhops up to the 3R destination node of this optical path, that is the 3Rsource node of the next 3R section, is small, it is determined that thisoptical node device had better implement the 3R relay. Accordingly, the3R relay load on the 3R source node of the next 3R section can bereduced.

In this way, if the previous optical node device of the 3R destinationnode implements the 3R relay instead of the 3R destination node, amessage showing to that effect is transmitted to the 3R destinationnode. Accordingly, the original 3R destination node recognizes that theprevious-hop optical node device with respect to the optical node deviceitself implemented the 3R relay instead of the optical node deviceitself, does not implement the 3R relay with respect to the incomingoptical signal on which is originally supposed to implement the 3Rrelay, and it switches as is. In this case, the application is modifiedfrom the 3R section which is initially planned to apply, to the 3Rsection which uses the optical node device that actually implemented the3R relay as the 3R source node.

Next is a description of the setting policy of the threshold of thenumber of vacant 3R trunks TH_T and the threshold of the number of hopsup to the 3R destination node TH_H. As the number of 3R trunks of the 3Rsource node of the next 3R section gets lower compared to the number of3R trunks of the optical node device itself, the necessity for theoptical node device itself to aid the 3R relay of the 3R source node ofthe next 3R section is increased. Therefore, TH_T is desirably set smallso that the optical node device itself can implement the 3R relay to aidthe 3R relay of the 3R source node of the next 3R section if there iseven a little vacancy generated in the 3R trunk of the optical nodedevice itself. However, in the case where the number of hops up to the3R source node of the next 3R section is large, even if the number ofthe 3R trunks of the optical node device itself has enough room, if theoptical node device itself implements the 3R relay instead of the 3Rsource node of the next 3R section, there is a possibility that thenumber of 3R implementations up to the destination node is increased.Therefore, TH_H is desirably small.

In this manner, TH_T and TH_H are appropriately set in consideration ofthe number of hops of the whole 3R section and the number of 3R trunksof the 3R destination node, that is, the 3R source node of the next 3Rsection.

Thirteenth Embodiment

An optical node device according to a thirteenth embodiment is describedwith reference to FIG. 4 that were described in the first embodiment,and FIGS. 47 and 48. The schematic block diagram of the optical nodedevice according to the present embodiment is similar to that of thefirst embodiment as shown in FIG. 4. However, the functions of therespective units constituting the optical node device differ from thatof the first embodiment. FIG. 47 is an explanatory diagram of a 3R relayimplementation node determination method of the present embodiment. FIG.48 is an explanatory diagram of the operation of optical node devices inthe thirteenth and fourteenth embodiments.

The optical path setting request includes labels to specify thewavelengths used sequentially from the source node when performingswitching from the source node to the destination node, and one label isdeleted as one wavelength is used.

Switching is performed based on the policy that switching is performedwith as small a number of wavelengths as possible on the optical pathfrom the source node to the destination node. That is, the best is tolink from the source node to the destination node with one wavelength.The wavelength conversion is performed only in the case where there isnot a vacant wavelength partway, and another wavelength is used. Thewavelength conversion trunk performs the wavelength conversion for suchswitching. However, the optical signal is once converted into theelectric signal by the wavelength conversion, and then converted intothe optical signal once again, so that the 3R relay is implemented atthe same time. Moreover, if it is required to implement the 3R relay ina part not requiring wavelength conversion, the wavelength is convertedinto the same wavelength for both input and output by the wavelengthconversion trunk.

Moreover, a method for determining the wavelength used from the sourcenode to the destination node, is based on the topology information ofthe optical network, and involves referring to the wavelength usagecondition of the optical network changing at each time, and making awavelength conversion plan from the source node to the destination node,and loading a label showing the wavelength to be used into the opticalpath setting request transmitted from the source node.

A transit optical node device refers to the label, determines whether ornot the optical node device itself performs the wavelength conversion,and ensures the wavelength conversion resources of the optical nodedevice itself if it is required to perform the wavelength conversion. Ifthe optical node device itself performs the wavelength conversion, thelabel corresponding to the wavelength to be converted which is loaded inthe optical path setting request is deleted and an optical path settingrequest is sent to the next-hop adjacent optical node device.

In the present embodiment, it is described that the necessaryinformation is stored in the 3R section information storing unit 20.However, the configuration may be such that a network control device(outside of the drawing) stores the necessary information so that thenecessary information can be obtained from the network control devicewhen the source node performs the optical path setting request so as tomake the wavelength conversion plan.

That is, as shown in FIG. 4, the optical node device according to thepresent embodiment comprises: a 3R section information storing unit 20which stores the information on the number of hops H between the opticalnode device itself and the 3R destination node in the 3R section towhich the optical node device itself belongs; and a 3R relayimplementation determining unit 21 which determines autonomously whetheror not the optical node device itself implements the 3R relay withrespect to the optical signal transmitted from the 3R source node in the3R section to which the optical node device itself belongs. This 3Rrelay implementation determining unit 21 determines to implement the 3Rrelay if T>TH_T and (H<TH_H and L<TH_L) assuming that the number ofwavelength conversion trunks provided by the optical node device itselfis T, the threshold of the number of vacant 3R trunks is TH_T, thethreshold of the number of hops up to the 3R destination node is TH_H,the number of remaining labels is L, and the threshold of the number ofremaining labels is TH_L. If the optical node device itself belongs tothe 3R section using the destination node as the 3R destination node,the 3R relay implementation determining unit 21 determines that theoptical node device itself does not implement the 3R relay.

Next is a description of the operation of the optical node deviceaccording to the thirteenth embodiment with reference to FIG. 47 andFIG. 48. As shown in FIG. 47, each optical node device comprises: aswitch unit 130 for switching the optical signal; and a plurality ofwavelength conversion trunks 140. In the example of FIG. 48, an opticalpath is set from the optical node device #1 being the source node andthe optical node device #10 being the destination node.

The 3R sections set on the optical path include: a section using opticalnode device #1 as the 3R source node and optical node device #5 as the3R destination node; a section using optical node device #2 as the 3Rsource node and optical node device #5 as the 3R destination node; asection using optical node device #4 as the 3R source node and opticalnode device #7 as the 3R destination node; a section using optical nodedevice #5 as the 3R source node and optical node device #8 as the 3Rdestination node; a 3R section using optical node device #7 as the 3Rsource node and optical node device #10 as the 3R destination node; a 3Rsection using optical node device #8 as the 3R source node and opticalnode device #10 as the 3R destination node; and a 3R section usingoptical node device #9 as the 3R source node and optical node device #10as the 3R destination node.

Moreover, the number of wavelength conversion trunks of the respectiveoptical node devices is 5 for each optical node device #1, #2, #3, #4,#5, #6, #7, and #9, and 10 for each optical node device #8 and #10.

Here, if the optical path using the optical node device #1 as the sourcenode and the optical node device #10 as the destination node is set, thebest way in order to keep the number of 3R implementations as small aspossible is to relay over the 3R section using the optical node device#1 as the 3R source node and the optical node device #5 as the 3Rdestination node, the 3R section using the optical node device #5 as the3R source node and the optical node device #8 as the 3R destinationnode, and the 3R section using the optical node device #8 as the 3Rsource node and the optical node device #10 as the 3R destination node.

The optical path setting request is sent from the optical node device #1to the optical node device #2. A plurality of labels (label set) whichshow the wavelength conversion required midway on the route are loadedinto this optical path setting request. In the example of FIG. 48, thewavelength λ1 and label L1 are used between the optical node device #1and the optical node device #3. The wavelength λ2 and label L2 are usedbetween the optical node device #3 and the optical node device #5. Thewavelength λ3 and label L3 are used between the optical node device #5and the optical node device #7. The wavelength λ4 and label L4 are usedbetween the optical node device #7 and the optical node device #10.

The optical node device #1 is the source node and the 3R source node, sothat it determines to implement the 3R relay from the beginning.

The optical node device #2 which receives the optical path settingrequest from the optical node device #1, recognizes that the opticalnode device #2 itself is capable of setting the optical path with thewavelength λ1, determines to set the optical path with the label L1(λ1), and determines whether or not it implements the 3R relay fromT>TH_T and (H<TH_H and L<TH_L). Here, it is assumed that TH_T=4, TH_H=2,and TH_L=1.

The number of wavelength conversion trunks of the optical node device 2is 5, so that T>TH_T is satisfied. Next, there are three hops from theoptical node device #2 to the optical node device #5 being the 3Rdestination node, so that H<TH_H is not satisfied. Therefore, theoptical node device #2 determines not to implement the 3R relay.

The optical node device #3 which receives the optical path settingrequest from the optical node device #2, recognizes that the opticalnode device #3 itself is not capable of setting the optical path withthe wavelength λ1, and determines to set the optical path with the labelL2 (λ2). Moreover, the optical node device #3 itself is not the 3Rsource node, so that it determines not to implement the 3R relay fromthe beginning.

The optical node device #4 which receives the optical path settingrequest from the optical node device #3, recognizes that the opticalnode device #4 itself is capable of setting the optical path with thewavelength λ2, determines to set the optical path with the label L2(λ2), and determines whether or not it implements the 3R relay fromT>TH_T and (H<TH_H and L<TH_L).

The number of wavelength conversion trunks of the optical node device #4is 5, so that T>TH_T is satisfied. Next, there is one hop from theoptical node device #4 to the optical node device #5 being the 3Rdestination node, so that H<TH_H is satisfied. Next, since the label L2is used for the optical node device #4, the number of remaining labelsare two of L3 and L4, so that L<TH_L is not satisfied. Therefore, theoptical node device #4 determines not to implement the 3R relay.

The optical node device #5 which receives the optical path settingrequest from the optical node device #4, recognizes that the opticalnode device #5 itself is not capable of setting the optical path withthe wavelength λ2, and determines to set the optical path with the labelL3 (λ3). Moreover, the optical node device #5 recognizes that theoptical node device #5 is the 3R source node of the next 3R sectionsince the optical node device #5 is the 3R destination node using theoptical node device #1 as the 3R source node, and that no previous-hopoptical node device among the optical node devices #2, #3, and #4implements the 3R relay, so that the optical node device #5 determinesto implement the 3R relay from the beginning.

The optical node device #6 which receives the optical path settingrequest from the optical node device #5, recognizes that the opticalnode device #6 itself is capable of setting the optical path with thewavelength λ3, and determines to set the optical path with the label L3(λ3). Moreover, the optical node device #6 itself is not the 3R sourcenode, so that the optical node device #6 determines not to implement the3R relay from the beginning.

The optical node device #7 which receives the optical path settingrequest from the optical node device #6, recognizes that the opticalnode device #7 itself is not capable of setting the optical path withthe wavelength λ3, determines to set the optical path with the label L4(λ4), and determines whether or not it implements the 3R relay from therelationship T>TH_T and (H<TH_H and L<TH_L).

The number of wavelength conversion trunks of the optical node device #7is 5, so that T>TH_T is satisfied. Next, there is one hop from theoptical node device #7 to the optical node device #8 being the 3Rdestination node, so that H<TH_H is satisfied. Next, since the label L4is used for the optical node device #7, the number of remaining labelsare zero, so that L<TH_L is satisfied. Therefore, the optical nodedevice #7 determines to implement the 3R relay. Moreover, the opticalnode device #7 transmits a message showing that it implements the 3Rrelay instead of the optical node device #8 to another optical nodedevice.

The optical node device #8 which receives the optical path settingrequest from the optical node device #7, recognizes that the opticalnode device #8 itself is capable of setting the optical path with thewavelength λ4, and determines to set the optical path with the label L4(λ4). Moreover, the optical node device #8 is the 3R destination nodeusing the optical node device #5 as the 3R source node, and receives themessage from the optical node device #7 showing that the optical nodedevice #7 implements the 3R relay instead of the optical node device #8itself, and determines not to implement the 3R relay although it issupposed to implement the 3R relay originally.

The optical node device #9 which receives the optical path settingrequest from the optical node device #8, recognizes that the opticalnode device #9 itself is capable of setting the optical path with thewavelength λ4, and determines to set the optical path with the label L4(λ4). Moreover, although the optical node device #9 is the 3R sourcenode, since it is determined that the optical node device itself doesnot implement the 3R relay when the next-hop is the destination node andthe optical node device itself belongs to the 3R section using thedestination node as the 3R destination node, the optical node device #9determines not to implement the 3R relay.

The optical node device #10 which receives the optical path settingrequest from the optical node device #9, recognizes that the opticalnode device #10 itself is capable of setting the optical path with thewavelength λ4, and determines to set the optical path with the label L4(λ4). Moreover, the optical node device #10 is the destination node, sothat the optical node device #10 determines not to implement the 3Rrelay.

Therefore, the 3R relay is implemented by the optical node devices #1,#5, and #7. The optical node device #7 implements the 3R relay insteadof the optical node device #8.

Fourteenth Embodiment

The operation of optical node devices according to a fourteenthembodiment is described. The schematic block diagram of the optical nodedevice according to the fourteenth embodiment is used in common with thethirteenth embodiment shown in FIG. 4. The explanatory diagram of theoperation of the optical node device according to the fourteenthembodiment is used in common with the thirteenth embodiment shown inFIG. 48.

In the example of FIG. 48, an optical path is set between the opticalnode device #1 being the source node and the optical node device #10being the destination node. The 3R sections set on the optical pathinclude: a section using optical node device #1 as the 3R source nodeand optical node device #5 as the 3R destination node; a section usingoptical node device #2 as the 3R source node and optical node device #5as the 3R destination node; a section using optical node device #4 asthe 3R source node and optical node device #7 as the 3R destinationnode; a section using optical node device #5 as the 3R source node andoptical node device #8 as the 3R destination node; a 3R section usingoptical node device #7 as the 3R source node and optical node device #10as the 3R destination node; a 3R section using optical node device #8 asthe 3R source node and optical node device #10 as the 3R destinationnode; and a 3R section using optical node device #9 as the 3R sourcenode and optical node device #10 as the 3R destination node.

Moreover, the number of wavelength conversion trunks of the respectiveoptical node devices is 5 for each optical node device #1, #2, #3, #4,#5, #6, #7, and #9, and 10 for each optical node device #8 and #10.

Here, if the optical path using the optical node device #1 as the sourcenode and the optical node device #10 as the destination node is set, thebest way in order to keep the number of 3R implementations as small aspossible is to relay over the section using the optical node device #1as the 3R source node and the optical node device #5 as the 3Rdestination node, the section using the optical node device #5 as the 3Rsource node and the optical node device #8 as the 3R destination node,and the section using the optical node device #8 as the 3R source nodeand the optical node device #10 as the 3R destination node.

The optical path setting request is sent from the optical node device #1to the optical node device #2. A plurality of labels (label set) whichshow the wavelength conversion required midway on the route are loadedinto this optical path setting request. In the example of FIG. 48, thewavelength λ1 and label L1 are used between the optical node device #1and the optical node device #3. The wavelength λ2 and label L2 are usedbetween the optical node device #3 and the optical node device #5. Thewavelength λ3 and label L3 are used between the optical node device #5and the optical node device #7. The wavelength λ4 and label L4 are usedbetween the optical node device #7 and the optical node device #10.

The optical node device #1 is the source node and the 3R source node, sothat it determines to implement the 3R relay.

The optical node device #2 which receives the optical path settingrequest from the optical node device #1, recognizes that the opticalnode device #2 itself is capable of setting the optical path with thewavelength λ1, determines to set the optical path with the label L1(λ1), and determines whether or not it implements the 3R relay fromT>TH_T and (H<TH_H or L<TH_L). Here, it is assumed that TH_T=4, TH_H=2,and TH_L=1.

The number of wavelength conversion trunks of the optical node device #2is 5, so that T>TH_T is satisfied. Next, there are three hops to theoptical node device #5 being the 3R destination node, so that H<TH_H isnot satisfied. Next, the number of remaining labels are three of L2, L3,and L4, so that L<TH_L is not satisfied. Therefore, the optical nodedevice #2 determines not to implement the 3R relay.

The optical node device #3 which receives the optical path settingrequest from the optical node device #2, recognizes that the opticalnode device #3 itself is not capable of setting the optical path withthe wavelength λ1, and determines to set the optical path with the labelL2 (λ2). Moreover, the optical node device #3 itself is not the 3Rsource node, so that the optical node device #3 determines not toimplement the 3R relay from the beginning.

The optical node device #4 which receives the optical path settingrequest from the optical node device #3, recognizes that the opticalnode device #4 itself is capable of setting the optical path with thewavelength λ2, determines to set the optical path with the label L2(λ2), and determines whether or not it implements the 3R relay fromT>TH_T and (H<TH_H or L<TH_L).

The number of wavelength conversion trunks of the optical node device #4is 5, so that T>TH_T is satisfied. Next, there is one hop from theoptical node device #4 to the optical node device #5 being the 3Rdestination node, so that H<TH_H is satisfied. Therefore, the opticalnode device #4 determines to implement the 3R relay. Moreover, theoptical node device #4 transmits a message showing that it implementsthe 3R relay instead of the optical node device #5, to another opticalnode device.

The optical node device #5 which receives the optical path settingrequest from the optical node device #4, recognizes that the opticalnode device #5 itself is capable of setting the optical path with thewavelength λ3, and determines to set the optical path with the label L3(λ3). Moreover, although the optical node device #5 is the 3Rdestination node using the optical node device #1 as the 3R source node,since the optical node device #5 receives the message from the opticalnode device #4 showing that the optical node device #4 implements the 3Rrelay instead of the optical node device #5 itself, so that the opticalnode device #5 determines not to implement the 3R relay although it issupposed to implement the 3R relay originally.

The optical node device #6 which receives the optical path settingrequest from the optical node device #5, recognizes that the opticalnode device #6 itself is capable of setting the optical path with thewavelength λ3, and determines to set the optical path with the label L3(λ3). Moreover, the optical node device #6 itself is not the 3R sourcenode, so that it determines not to implement the 3R relay from thebeginning.

The optical node device #7 which receives the optical path settingrequest from the optical node device #6, recognizes that the opticalnode device #7 itself is not capable of setting the optical path withthe wavelength λ3, and determines to set the optical path with the labelL4 (λ4). The optical node device #7 also receives the message showingthat the optical node device #4 implements the 3R relay instead of theoptical node device #5, to find out that the optical node device #7 isthe 3R destination node and the 3R source node of the next 3R section ifthe optical node device #4 is the 3R source node. Therefore the opticalnode device #7 determines to implement the 3R relay. Moreover, theoptical node device #7 transmits a message showing that the optical nodedevice #7 itself implements the 3R relay, to another optical nodedevice.

The optical node device #8 which receives the optical path settingrequest from the optical node device #7, recognizes that the opticalnode device #8 itself is capable of setting the optical path with thewavelength λ4, and determines to set the optical path with the label L4(λ4). Moreover, the optical node device #8 receives the message from theoptical node device #7 showing that the optical node device #7implements the 3R relay, to thereby recognize that the optical nodedevice #8 belongs to the 3R section using the optical node device #7 asthe 3R source node and the optical node device #10 as the 3R destinationnode. Therefore, the optical node device #8 determines not to implementthe 3R relay from the beginning.

The optical node device #9 which receives the optical path settingrequest from the optical node device #8, recognizes that the opticalnode device #9 itself is capable of setting the optical path with thewavelength λ4, and determines to set the optical path with the label L4(λ4). Moreover, the optical node device #9 receives the message from theoptical node device #7 showing that the optical node device #7implements the 3R relay, to thereby recognize that the optical nodedevice #9 belongs to the 3R section using the optical node device #7 asthe 3R source node and the optical node device #10 as the 3R destinationnode. Therefore, the optical node device #9 determines not to implementthe 3R relay from the beginning.

The optical node device #10 which receives the optical path settingrequest from the optical node device #9, recognizes that the opticalnode device #10 itself is capable of setting the optical path with thewavelength λ4, and determines to set the optical path with the label L4(λ4). Moreover, the optical node device #10 is the destination node, sothat it determines not to implement the 3R relay.

Therefore, the 3R relay is implemented by the optical node devices #1,#4, and #7. The optical node device #4 takes on the role of the opticalnode device #5.

Fifteenth Embodiment

The operation of the optical node device according to the fifteenthembodiment is described with reference to FIG. 49. FIG. 49 is anexplanatory diagram of the operation of optical node devices in thefifteenth and sixteenth embodiments. The fifteenth embodiment is anembodiment for the bi-directional optical path. From the aspect of thebi-directional optical path, the embodiment in the downstream opticalpath was described in the thirteenth embodiment. Here, the embodimentfor the upstream optical path is described in the fifteenth embodiment.Therefore, in the actual setting of the bi-directional optical path, theprocedure described in the thirteenth embodiment and the procedure to bedescribed in the fifteenth embodiment are executed in parallelapproximately at the same time.

The 3R sections set on the upstream optical path shown in FIG. 49include: a section using optical node device #10 as the 3R source nodeand optical node device #6 as the 3R destination node; a section usingoptical node device #9 as the 3R source node and optical node device #6as the 3R destination node; a section using optical node device #7 asthe 3R source node and optical node device #4 as the 3R destinationnode; a section using optical node device #6 as the 3R source node andoptical node device #3 as the 3R destination node; a 3R section usingoptical node device #4 as the 3R source node and optical node device #1as the 3R destination node, a 3R section using optical node device #3 asthe 3R source node and optical node device #1 as the 3R destinationnode, and a 3R section using optical node device #2 as the 3R sourcenode and optical node device #1 as the 3R destination node.

Moreover, the number of wavelength conversion trunks of the respectiveoptical node devices is 5 for each optical node device #1, #2, #3, #4,#5, #6, #7, and #9, and 10 for each optical node device #8 and #10.

Here, if the upstream optical path using the optical node device #1 asthe source node and the optical node device #10 as the destination nodeis set, the best way in order to keep the number of 3R implementationsas small as possible is to relay over the section using the optical nodedevice #10 as the 3R source node and the optical node device #6 as the3R destination node, the section using the optical node device #6 as the3R source node and the optical node device #3 as the 3R destinationnode, and the section using the optical node device #3 as the 3R sourcenode and the optical node device #1 as the 3R destination node.

The optical path setting request is sent from the optical node device #1to the optical node device #2. A plurality of labels (label set) whichshow the wavelength conversion required midway on the route are loadedinto this optical path setting request. In the example of FIG. 49, thewavelength λ1 and label L1 are used between the optical node device #1and the optical node device #3. The wavelength λ2 and label L2 are usedbetween the optical node device #3 and the optical node device #5. Thewavelength λ3 and label L3 are used between the optical node device #5and the optical node device #7. The wavelength λ4 and label L4 are usedbetween the optical node device #7 and the optical node device #10.

The optical node device #1 is the source node and the 3R destinationnode on the upstream optical path, so that it determines not toimplement the 3R relay.

The optical node device #2 which receives the optical path settingrequest from the optical node device #1, recognizes that the opticalnode device #2 itself is capable of setting the optical path with thewavelength λ1, and determines to set the optical path with the label L1(λ1). Moreover, on the upstream optical path, the optical node device #2itself belongs to the 3R section using the optical node device #3 as the3R source node and the optical node device #1 as the 3R destinationnode. Therefore the optical node device #2 determines not to implementthe 3R relay.

The optical node device #3 which receives the optical path settingrequest from the optical node device #2, recognizes that the opticalnode device #3 itself is not capable of setting the optical path withthe wavelength λ1, and determines to set the optical path with the labelL2 (λ2). Moreover, the optical node device #3 itself is the 3R sourcenode on the predetermined upstream optical path, so that it determinesto implement the 3R relay.

The optical node device #4 which receives the optical path settingrequest from the optical node device #3, recognizes that the opticalnode device #4 itself is capable of setting the optical path with thewavelength λ2, and determines to set the optical path with the label L2(λ2). Since the optical node device #4 is the 3R source node, theoptical node device #4 determines whether or not it implements the 3Rrelay from T>TH_T and (H<TH_H and L>TH_L). It is assumed that TH_T=4,TH_H=2, and TH_L=1.

The number of wavelength conversion trunks of the optical node device #4is 5, so that T>TH_T is satisfied. Next, there is one hop from theoptical node device #4 to the optical node device #3 being the 3Rdestination node on the upstream optical path, so that H<TH_H issatisfied. Next, since the label L2 is used for the optical node device#4, the number of remaining labels are two of L3 and L4, so that L>TH_Lis satisfied. Therefore, the optical node device #4 determines toimplement the 3R relay. The determination result is transmitted to theoptical node device #3.

When the optical node device #3 receives this transmitted determinationresult from the optical node device #4, it withdraws the determinationto implement the 3R relay previously determined by the optical nodedevice #4 itself.

The optical node device #5 which receives the optical path settingrequest from the optical node device #4, recognizes that the opticalnode device #5 itself is not capable of setting the optical path withthe wavelength λ2, and determines to set the optical path with the labelL3 (λ3). Moreover, the optical node device #5 is not the 3R source node,so that the optical node device #5 determines not to implement the 3Rrelay from the beginning.

The optical node device #6 which receives the optical path settingrequest from the optical node device #5, recognizes that the opticalnode device #6 itself is capable of setting the optical path with thewavelength λ3, and determines to set the optical path with the label L3(λ3). Moreover, the optical node device #6 itself is the 3R source nodeon the predetermined upstream optical path, so that the optical nodedevice #6 determines to implement the 3R relay from the beginning.

The optical node device #7 which receives the optical path settingrequest from the optical node device #6, recognizes that the opticalnode device #7 itself is not capable of setting the optical path withthe wavelength λ3, determines to set the optical path with the label L4(λ4), and determines whether or not it implements the 3R relay fromT>TH_T and (H<TH_H and L>TH_L).

The number of wavelength conversion trunks of the optical node device #7is 5, so that T>TH_T is satisfied. Next, there is one hop from theoptical node device #7 to the optical node device #6 being the 3Rdestination node, so that H<TH_H is satisfied. Next, since the label L4is used for the optical node device #7, the number of remaining labelsare zero, so that L>TH_L is not satisfied. Therefore, the optical nodedevice #7 determines not to implement the 3R relay.

The optical node device #8 which receives the optical path settingrequest from the optical node device #7, recognizes that the opticalnode device #8 itself is capable of setting the optical path with thewavelength λ4, and determines to set the optical path with the label L4(λ4). Moreover, the optical node device #8 is not the 3R source node, sothat it determines not to implement the 3R relay from the beginning.

The optical node device #9 which receives the optical path settingrequest from the optical node device #8, recognizes that the opticalnode device #9 itself is capable of setting the optical path with thewavelength λ4, determines to set the optical path with the label L4(λ4), and determines whether or not it implements the 3R relay fromT>TH_T and (H<TH_H and L>TH_L).

The number of wavelength conversion trunks of the optical node device #9is 5, so that T>TH_T is satisfied. Next, there are three hops from theoptical node device #9 to the optical node device #6 being the 3Rdestination node, so that H<TH_H is not satisfied. Therefore, theoptical node device #9 determines not to implement the 3R relay.

The optical node device #10 which receives the optical path settingrequest from the optical node device #9, recognizes that the opticalnode device #10 itself is capable of setting the optical path with thewavelength λ4, and determines to set the optical path with the label L4(λ4). Moreover, since the optical node device #10 is the destinationnode, the optical node device #10 is the 3R source node on the upstreamoptical path, so that it determines to implement the 3R relay.

Therefore, the 3R relay is implemented by the optical node devices #4,#6, and #10. The optical node device #4 implements the 3R relay insteadof the optical node device #3.

Sixteenth Embodiment

The operation of the optical node device according to the sixteenthembodiment is described with reference to FIG. 49. The sixteenthembodiment is an embodiment in the bi-directional optical path. From theaspect of the bi-directional optical path, the embodiment for thedownstream optical path was described in the fourteenth embodiment.Here, the embodiment for the upstream optical path is described in thesixteenth embodiment. Therefore, in the actual setting of thebi-directional optical path, the procedure described in the fourteenthembodiment and the procedure to be described in the sixteenth embodimentare executed in parallel approximately at the same time.

The 3R sections set on the upstream optical path shown in FIG. 49include: a section using optical node device #10 as the 3R source nodeand optical node device #6 as the 3R destination node; a section usingoptical node device #9 as the 3R source node and optical node device #6as the 3R destination node; a section using optical node device #7 asthe 3R source node and optical node device #4 as the 3R destinationnode; a section using optical node device #6 as the 3R source node andoptical node device #3 as the 3R destination node; a 3R section usingoptical node device #4 as the 3R source node and optical node device #1as the 3R destination node; a 3R section using optical node device #3 asthe 3R source node and optical node device #1 as the 3R destinationnode; and a 3R section using optical node device #2 as the 3R sourcenode and optical node device #1 as the 3R destination node.

Moreover, the number of wavelength conversion trunks of the respectiveoptical node devices is 5 for each optical node device #1, #2, #3, #4,#5, #6, #7, and #9, and 10 for each optical node device #8 and #10.

Here, if the upstream optical path using the optical node device #1 asthe source node and the optical node device #10 as the destination nodeis set, the best way in order to keep the number of 3R implementationsas small as possible is to relay over the section using the optical nodedevice #10 as the 3R source node and the optical node device #6 as the3R destination node, the section using the optical node device #6 as the3R source node and the optical node device #3 as the 3R destinationnode, and the section using the optical node device #3 as the 3R sourcenode and the optical node device #1 as the 3R destination node.

The optical node device #1 is the source node and the 3R destinationnode on the upstream optical path, so that it determines not toimplement the 3R relay.

The optical path setting request is sent from the optical node device #1to the optical node device #2. A plurality of labels (label set) whichshows the wavelength conversion required midway on the route are loadedinto this optical path setting request. In the example of FIG. 49, thewavelength λ1 and label L1 are used between the optical node device #1and the optical node device #3. The wavelength λ2 and label L2 are usedbetween the optical node device #3 and the optical node device #5. Thewavelength λ3 and label L3 are used between the optical node device #5and the optical node device #7. The wavelength λ4 and label L4 are usedbetween the optical node device #7 and the optical node device #10.

The optical node device #2 which receives the optical path settingrequest from the optical node device #1, recognizes that the opticalnode device #2 itself is capable of setting the optical path with thewavelength λ1, and determines to set the optical path with the label L1(λ1). Moreover, on the upstream optical path, the optical node device #2itself belongs to the 3R section using the optical node device #3 as the3R source node and the optical node device #1 as the 3R destinationnode. Therefore the optical node device #2 determines not to implementthe 3R relay.

The optical node device #3 which receives the optical path settingrequest from the optical node device #2, recognizes that the opticalnode device #3 itself is not capable of setting the optical path withthe wavelength λ1, and determines to set the optical path with the labelL2 (λ2). Moreover, the optical node device #3 itself is the 3R sourcenode on the predetermined upstream optical path, so that it determinesto implement the 3R relay.

The optical node device #4 which receives the optical path settingrequest from the optical node device #3, recognizes that the opticalnode device #4 itself is capable of setting the optical path with thewavelength λ2, and determines to set the optical path with the label L2(λ2). Since the optical node device #4 is the 3R source node, theoptical node device #4 determines whether or not it implements the 3Rrelay from T>TH_T and (H<TH_H or L>TH_L). It is assumed that TH_T=4,TH_H=2, and TH_L=1.

The number of wavelength conversion trunks of the optical node device #4is 5, so that T>TH_T is satisfied. Next, there is one hop from theoptical node device #4 to the optical node device #3 being the 3Rdestination node on the upstream optical path, so that H<TH_H issatisfied. Therefore, the optical node device #4 determines to implementthe 3R relay. The determination result is transmitted to the opticalnode device #3.

When the optical node device #3 receives this transmitted determinationresult from the optical node device #4, it withdraws the determinationto implement the 3R relay previously determined by the optical nodedevice #3 itself.

The optical node device #5 which receives the optical path settingrequest from the optical node device #4, recognizes that the opticalnode device #5 itself is not capable of setting the optical path withthe wavelength λ2, and determines to set the optical path with the labelL3 (λ3). Moreover, the optical node device #5 is not the 3R source node,so that it determines not to implement the 3R relay from the beginning.

The optical node device #6 which receives the optical path settingrequest from the optical node device #5, recognizes that the opticalnode device #6 itself is capable of setting the optical path with thewavelength λ3, and determines to set the optical path with the label L3(λ3). Moreover, the optical node device #6 itself is the 3R source nodeon the predetermined upstream optical path, so that it determines toimplement the 3R relay from the beginning.

The optical node device #7 which receives the optical path settingrequest from the optical node device #6, recognizes that the opticalnode device #7 itself is not capable of setting the optical path withthe wavelength λ3, determines to set the optical path with the label L4(λ4), and determines whether or not it implements the 3R relay fromT>TH_T and (H<TH_H or L>TH_L).

The number of wavelength conversion trunks of the optical node device #7is 5, so that T>TH_T is satisfied. Next, there is one hop from theoptical node device #7 to the optical node device #6 being the 3Rdestination node, so that H<TH_H is satisfied. Therefore, the opticalnode device #7 determines to implement the 3R relay. This determinationresult is transmitted to the optical node device #6.

When the optical node device #6 receives this transmitted determinationresult from the optical node device #7, it withdraws the determinationto implement the 3R relay previously determined by the optical nodedevice #6 itself.

The optical node device #8 which receives the optical path settingrequest from the optical node device #7, recognizes that the opticalnode device #8 itself is capable of setting the optical path with thewavelength λ4, and determines to set the optical path with the label L4(λ4). Moreover, the optical node device #8 is not the 3R source node, sothat it determines not to implement the 3R relay from the beginning.

The optical node device #9 which receives the optical path settingrequest from the optical node device #8, recognizes that the opticalnode device #9 itself is capable of setting the optical path with thewavelength λ4, determines to set the optical path with the label L4(λ4), and determines whether or not it implements the 3R relay fromT>TH_T and (H<TH_H or L>TH_L).

The number of wavelength conversion trunks of the optical node device #9is 5, so that T>TH_T is satisfied. Next, there are three hops from theoptical node device #9 to the optical node device #6 being the 3Rdestination node, so that H<TH_H is not satisfied. Next, the number ofremaining labels are zero, so that L>TH_L is not satisfied. Therefore,the optical node device #9 determines not to implement the 3R relay.

The optical node device #10 which receives the optical path settingrequest from the optical node device #9, recognizes that the opticalnode device #10 itself is capable of setting the optical path with thewavelength λ4, and determines to set the optical path with the label L4(λ4). Moreover, since the optical node device #10 is the destinationnode and is the 3R source node on the upstream optical path, so that itdetermines to implement the 3R relay.

Therefore, the 3R relay is implemented by the optical node devices #4,#7, and #10. The optical node device #4 implements the 3R relay insteadof the optical node device #3, and the optical node device #7 takes onthe role of the 3R relay of the optical node device #6.

Seventeenth Embodiment

Optical node devices according to a seventeenth embodiment are describedwith reference to FIG. 50 to FIG. 52. FIG. 50 and FIG. 52 areexplanatory diagrams of the schematic block configuration and theoperation of optical node devices according to the seventeenthembodiment. FIG. 51 is a block diagram of a measuring unit. As shown inFIG. 50, the optical node device according to the seventeenth embodimentcomprises: a measuring unit 218 which detects the deterioration state ofthe optical signal arriving at the optical node device itself; a controlsystem 217 which notifies the 3R relay request to an adjacent opticalnode device one hop before the optical node device itself when thedetection result of this measuring unit 218 shows signal deterioration;and a 3R relay unit 224 which implements the 3R relay with respect tothe optical signal arriving at the optical node device itself when theoptical node device itself receives the 3R relay request from thecontrol system 217 of the next-hop adjacent optical node device.

As shown in FIG. 51, the measuring unit 218 measures the light noise ofthe optical signal by a light noise observation unit 225, and the lightintensity of the optical signal by a light intensity observation unit226. This measurement result is aggregated by a measured data generationunit 231. The measuring unit 218 in other embodiments has a similarconfiguration.

Next is a description of the operation of the optical node deviceaccording to the seventeenth embodiment. If an optical path passingthrough the optical node device itself is set, the optical node deviceaccording to the seventeenth embodiment branches and inputs the opticalsignal transmitted on the optical path into the measuring unit 218, andobserves the signal deterioration state. Now, if optical signaldeterioration is detected in the optical node device #4, the opticalnode device #4 requests the optical node device #3 to implement the 3Rrelay. The optical node device #3 which receives this request leads theoptical path passing through the optical node device #3 itself to the 3Rrelay unit 224 and implements the 3R relay.

The seventeenth embodiment up to here is described on the assumption ofa downstream optical path of the unidirectional optical path or thebi-directional optical path. The following is a description on theassumption of the upstream optical path, with reference to FIG. 52. Asshown in FIG. 52, the optical node device according to the seventeenthembodiment comprises: a measuring unit 218 which detects thedeterioration state of the optical signal of the upstream optical patharriving at the optical node device itself; a control system 217 whichsends the 3R relay implementation request to an adjacent optical nodedevice corresponding to the next-hop of the optical node device itselfwhen the detection result of this measuring unit 218 shows signaldeterioration; and a 3R relay unit 224 which implements the 3R relaywith respect to the optical signal arriving at the optical node deviceitself when the optical node device itself receives the 3R relayimplementation request from the control system 217 of the previous-hopadjacent optical node device.

Next is a description of the operation of the optical node deviceaccording to the seventeenth embodiment. If an upstream optical pathpassing through the optical node device itself is set, the optical nodedevice according to the seventeenth embodiment branches and inputs theoptical signal transmitted on the upstream optical path into themeasuring unit 218, and observes the signal deterioration state thereof.Now, if optical signal deterioration is detected in the optical nodedevice #1, the optical node device #1 sends the 3R relay implementationrequest to the optical node device #2. The optical node device #2 whichreceives this 3R relay implementation request leads the upstream opticalpath passing through the optical node device #2 itself to the 3R relayunit 224 and implements the 3R relay.

Describing the situation where the preset 3R section is changed in thisway, for example in the case where a large number of new optical pathsare set to one optical node device, there might be a case where theexisting optical path receives noise caused by cross talk or nonlineareffects due to the effect of the new optical paths. In such a case, achange occurs in the 3R section. In the seventeenth embodiment, it ispossible to flexibly deal with such changes of the 3R section.

If the respective optical node devices each have the 3R relay unit 224,there is concern of whether or not the network resources can beeffectively used compared to the conventional technique. However, whileconventionally all optical node devices implement the 3R relay equally,only the selected optical node device implements the 3R relay in theseventeenth embodiment, and load due to the 3R relay is distributed to aplurality of the optical node devices, so that the network resources canbe effectively used.

That is, in most cases, the 3R relay unit 224 of the respective opticalnode devices may implement the 3R relay only on a part of the opticalpath passing through the optical node device itself. On the other hand,conventionally, the 3R relay unit 224 of the respective optical nodedevices is required to implement the 3R relay to all of the opticalpaths passing through the optical node device itself. Therefore, thescale of the 3R relay unit 224 can be smaller to deal with compared tothe conventional technique, so that the network resources can beeffectively used and the cost can be reduced.

Eighteenth Embodiment

An optical node device according to an eighteenth embodiment isdescribed with reference to FIG. 53 to FIG. 55. FIG. 53 is a blockdiagram of an optical node device comprising an optical switch unit onthe output side in the eighteenth embodiment. FIG. 54 is a block diagramof an optical node device comprising the optical switch unit on theinput side in the eighteenth embodiment. FIG. 55 is a block diagram ofan optical node device comprising a trunk-type 3R relay unit in theeighteenth embodiment.

The optical node device according to the eighteenth embodimentcomprises: a measuring unit 218 which detects the deterioration state ofthe optical signal arriving at the optical node device itself; and a 3Rrelay unit 224 which implements the 3R relay with respect to the opticalsignal arriving at the optical node device itself when the detectionresult of this measuring unit 218 shows signal deterioration.

Next is a description of the operation of the optical node deviceaccording to the eighteenth embodiment. In the optical node device shownin FIG. 53, when the measuring unit 218 detects deterioration of theinput optical signal, the detection result is transmitted to the controlsystem 217. The control system 217 outputs an instruction to theselector 227 and the input optical signal is connected to the 3R relayunit 224. Accordingly, the optical signal which is subjected to the 3Rrelay is input into the optical switch unit 228 via the 3R relay unit224.

In the optical node device shown in FIG. 54, when the measuring unit 218detects the deterioration of the optical signal output from the opticalswitch unit 228, the detection result is transmitted to the controlsystem 217. The control system 217 outputs an instruction to theselector 227 and the input optical signal is connected to the 3R relayunit 224. Accordingly, the optical signal which is subjected to the 3Rrelay is output via the 3R relay unit 224.

In the optical node device shown in FIG. 55, when the measuring unit 218detects deterioration of the input optical signal, the detection resultis transmitted to the control system 217. The control system 217 outputsan instruction to the optical switch unit 228 and the input opticalsignal is connected to the 3R relay unit 224. Accordingly, the opticalsignal which is once output from the optical switch unit 228 and then 3Rrelayed via the 3R relay unit 224, is input into the optical switch unit228 again. The optical switch unit 228 switches the 3R relayed opticalsignal to the target route.

The eighteenth embodiment up to here is described on the assumption of adownstream optical path of the unidirectional optical path or thebi-directional optical path. Since it can be readily inferred that the3R section information of the upstream optical path can be generated ina similar procedure to that of the downstream optical path, detaileddescription is omitted.

That is, the optical node device according to the eighteenth embodimentcomprises: the measuring unit 218 which detects the deterioration stateof the optical signal of the upstream optical path arriving at theoptical node device itself; and the 3R relay unit 224 which implementsthe 3R relay with respect to the optical signal of the upstream opticalpath arriving at the optical node device itself when the detectionresult of this measuring unit 218 shows signal deterioration.

Nineteenth Embodiment

Optical node devices according to a nineteenth embodiment are describedwith reference to FIG. 56 to FIG. 59. FIG. 56 and FIG. 58 show conceptsof 3R section information collection in the optical node devicesaccording to the nineteenth embodiment. FIG. 57 and FIG. 59 show 3Rsection information collecting procedures in the optical node devicesaccording to the nineteenth embodiment.

The optical node device according to the nineteenth embodiment is anoptical node device which switches the optical signal and sequentiallysets the optical path one hop at a time from the next-hop adjacentoptical node device to another optical node device included in a routefrom the optical node device itself to the destination node, and, asshown in FIG. 56, comprises in the 3R relay implementation determiningunit 229: a unit which sends an optical test signal at each time whenthe optical path is sequentially set for the other optical node devicesincluded in the route to the destination node one hop at a time from thenext-hop adjacent optical node device; a unit which receives a report onthe deterioration state of the optical test signal from another opticalnode device at the farthest end receiving the optical test signal ateach time when the optical test signal is sequentially sent to the otheroptical node device included in the route to the destination node onehop at a time from the next-hop adjacent optical node device by thissending unit; and a unit which requests another optical node deviceone-hop before the other optical node device at the farthest end toimplement the 3R relay if the deterioration state of the optical testsignal based on the reported result received by this receiving unitsatisfies a predetermined deterioration condition. The 3R relayimplementation determining unit 229 of the other optical node devicewhich is requested to implement the 3R relay comprises: a unit whichsends the optical test signal at each time when the optical path issequentially set for the other optical node devices included in theroute to the destination node one hop at a time from the next-hopadjacent optical node device; a unit which receives the report on thedeterioration state of the optical test signal from another optical nodedevice at the farthest end receiving the optical test signal at eachtime when the optical test signal is sequentially sent to the otheroptical node device included in the route to the destination node onehop at a time from the next-hop adjacent optical node device by thissending unit; and a unit which requests another optical node device onehop before the other optical node device at the farthest end toimplement the 3R relay when the deterioration state of the optical testsignal based on the reported result received by this receiving unitsatisfies a predetermined deterioration condition. In practice, eachoptical node device comprises the 3R relay implementation determiningunit 229, and the above functions of the respective units are activatedwhen each optical node device itself becomes the source node or the 3Rsource node.

Next is a description of the optical node device according to thenineteenth embodiment. The 3R relay implementation requesting procedureshown in FIG. 57 is executed by the 3R relay implementation determiningunit 229. Here is a description of an embodiment of a process in whichthe optical node device #1 is the 3R source node and the 3R relayimplementation is requested while setting the optical path. As shown inFIG. 57, the 3R relay implementation determining unit 229 of the opticalnode device #1 sets an optical path to the optical node device #2, whichis one hop ahead of the optical node device itself (Step 101 and Step102). In FIG. 56, the optical node device #1 sends an optical pathsetting request (PATH) to the optical node device #2. When the opticalnode device #2 receives the optical path setting request (PATH), itensures the resources required for optical path setting and sends theoptical path setting completion notification (RESV) to the optical nodedevice #1. Accordingly, the optical path is set between the optical nodedevices #1 and #2.

Subsequently, the optical node device #1 sends an optical test signal(LIGHT) to the set optical path (Step 103), and receives an optical testsignal deterioration state report (RESULT) from the optical node device#2 (Step 104). Since no deterioration is shown in the optical testsignal deterioration state report from the optical node device #2 (Step105), the optical node device #1 sets an optical path to the opticalnode device #3, which is two hops ahead of the optical node device #1itself (Step 106 and Step 102). In FIG. 56, the optical node device #1sends the optical path setting request (PATH) to the optical node device#3 via the optical node device #2. When the optical node device #3receives the optical path setting request (PATH), the optical nodedevice #3 ensures the resources required for optical path setting andsends the optical path setting completion notification (RESV) to theoptical node device #1 via the optical node device #2. Accordingly, theoptical path is set between the optical node devices #1 and #3.

Subsequently, the optical node device #1 sends an optical test signal(LIGHT) to the set optical path (Step 103), and receives an optical testsignal deterioration state report (RESULT) from the optical node device#3 (Step 104). Since no deterioration is shown in the optical testsignal deterioration state report from the optical node device #3 (Step105), the optical node device #1 sets an optical path to the opticalnode device #4, which is three hops ahead of the optical node device #1itself (Step 106 and Step 102). In FIG. 56, the optical node device #1sends the optical path setting request (PATH) to the optical node device#4 via the optical node devices #2 and #3. When the optical node device#4 receives the optical path setting request (PATH), it ensures theresources required for optical path setting and sends the optical pathsetting completion notification (RESV) to the optical node device #1 viathe optical node devices #3 and #2. Accordingly, the optical path is setbetween the optical node devices #1 and #4.

Subsequently, the optical node device #1 sends an optical test signal(LIGHT) to the set optical path (Step 103), and receives an optical testsignal deterioration state report (RESULT) from the optical node device#4 (Step 104). Since no deterioration is shown in the optical testsignal deterioration state report from the optical node device #4 (Step105), the optical node device #1 sets an optical path to the opticalnode device #5, which is four hops ahead of the optical node device #1itself (Step 106 and Step 102). In FIG. 56, the optical node device #1sends the optical path setting request (PATH) to the optical node device#5 via the optical node devices #2, #3, and #4. When the optical nodedevice #5 receives the optical path setting request (PATH), it ensuresthe resources required for optical path setting and sends the opticalpath setting completion notification (RESV) to the optical node device#1 via the optical node devices #4, #3, and #2. Accordingly, the opticalpath is set between the optical node devices #1 and #5.

Subsequently, the optical node device #1 sends an optical test signal(LIGHT) to the set optical path (Step 103), and receives an optical testsignal deterioration state report (RESULT) from the optical node device#5 (Step 104). Since no deterioration is shown in the optical testsignal deterioration state report from the optical node device #5 (Step105), the optical node device #1 sets an optical path to the opticalnode device #6, which is five hops ahead of the optical node device #1itself (Step 106 and Step 102). In FIG. 56, the optical node device #1sends the optical path setting request (PATH) to the optical node device#6 via the optical node devices #2, #3, #4, and #5. When the opticalnode device #6 receives the optical path setting request (PATH), itensures the resources required for optical path setting and sends theoptical path setting completion notification (RESV) to the optical nodedevice #1 via the optical node devices #5, #4, #3, and #2. Accordingly,the optical path is set between the optical node devices #1 and #6.

Subsequently, the optical node device #1 sends an optical test signal(LIGHT) to the set optical path (Step 103), and receives an optical testsignal deterioration state report (RESULT) from the optical node device#6 (Step 104). Deterioration is shown in the optical test signaldeterioration state report from the optical node device #6 (Step 105),so the optical node device #1 requests the optical node device #5, whichis four hops ahead of the optical node device #1 itself to implement the3R relay (Step 107). When the optical node device #5 receives therequest to implement the 3R relay from the optical node device #1, itsends an approval with respect to the request to the optical node device#1.

Moreover, the optical node device #5 receives the 3R relayimplementation request from the optical node device #1 (Step 108), sothat it recognizes that the optical node device #5 itself is the 3Rsource node, and executes the procedure from Step 101. Furthermore, theprocess is terminated since the optical node device #1 requests theoptical node device #5 to implement the 3R relay, and the optical nodedevice #1 does not receive the 3R relay implementation request fromanother optical node device.

In this way, in the nineteenth embodiment, it is possible to determinethe optical node device for implementing the 3R relay in the process ofthe optical path setting. In the example of FIG. 56, all of therespective optical node devices #1 to #7 comprise a 3R relayimplementation determining unit 229. However the configuration may besuch that for example every other optical node device comprises it.Moreover, in the present embodiment, in order to facilitate description,the optical test signal was sent to the optical node device #2 or #3which is not expected to require the 3R relay. However, the sendingprocedure of the optical test signal may be omitted with respect tothese optical node devices #2 and #3. Alternatively, the optical testsignal may be sent to only the optical node device #5 or #6 which isexpected to require the 3R relay.

The nineteenth embodiment up to here is described on the assumption of adownstream optical path of the unidirectional optical path or thebi-directional optical path. The following is a description on theassumption of the upstream optical path, with reference to FIG. 58 andFIG. 59. The optical node device according to the nineteenth embodimentsequentially sets the optical path one hop at a time from the next-hopadjacent optical node device to another optical node device included ina route to the destination node, if the optical node device itself isthe source node. The 3R relay implementation determining unit 229comprises a unit which sends the optical test signal to the upstreamoptical path when the optical path is set to the optical node deviceitself, if the optical node device itself is not the source node.Moreover, this 3R relay implementation determining unit 229 comprises aunit which receives the optical test signal if the optical node deviceitself is the source node and notifies the report on the optical testsignal deterioration state to the sender of the optical test signal.Furthermore, the 3R relay implementation determining unit 229 of thesender optical node device of the optical test signal determines toimplement the 3R relay with respect to the optical signal arriving fromthe upstream optical path, if the optical test signal deteriorationstate based on this notification satisfies a predetermined deteriorationcondition. Furthermore, the 3R relay implementation determining unit 229comprises a unit which sequentially sets the optical path one hop at atime from the next-hop adjacent optical node device to another opticalnode device included in the route from the optical node device itself tothe destination node, if the optical node device itself is the opticalnode device for implementing the 3R relay on the upstream optical path,receives the optical test signal, and notifies the report on the opticaltest signal deterioration state to the sender of the optical testsignal. In practice, each optical node device comprises the 3R relayimplementation determining unit 229, and the above functions of therespective units are activated when each optical node device itselfbecomes the source node, the 3R source node, or the 3R destination node.

Next is a description of the operation of the optical node devicesaccording to the nineteenth embodiment. The 3R relay implementationrequesting procedure shown in FIG. 59 is executed by the 3R relayimplementation determining unit 229. Here is a description of an exampleof a process in which the optical node device #1 is the 3R destinationnode on the upstream optical path and the 3R relay implementation isrequested while setting the optical path. As shown in FIG. 59, the 3Rrelay implementation determining unit 229 of the optical node device #1sets an optical path to the optical node device #2, which is one hopahead of the optical node device #1 itself (Step 111 and Step 112). InFIG. 58, the optical node device #1 sends an optical path settingrequest (PATH) to the optical node device #2. When the optical nodedevice #2 receives the optical path setting request (PATH), it ensuresthe resources required for optical path setting and sends the opticalpath setting completion notification (RESV) to the optical node device#1. Accordingly, the optical path is set between the optical nodedevices #1 and #2.

Subsequently, the optical node device #1 receives an optical test signal(LIGHT) from the set upstream optical path (Step 113), and measures thedeterioration of the optical test signal from the optical node device #2and reports the measurement result (RESULT) to the optical node device#2 (Step 114). Since no deterioration is shown in the optical testsignal from the optical node device #2 (Step 115), the optical nodedevice #1 sets an optical path to the optical node device #3, which istwo hops ahead of the optical node device #1 itself (Step 116 and Step112). In FIG. 58, the optical node device #1 sends the optical pathsetting request (PATH) to the optical node device #3 via the opticalnode device #2. When the optical node device #3 receives the opticalpath setting request (PATH), it ensures the resources required foroptical path setting and sends the optical path setting completionnotification (RESV) to the optical node device #1 via the optical nodedevice #2. Accordingly, the optical path is set between the optical nodedevices #1 and #3.

Subsequently, the optical node device #1 receives an optical test signal(LIGHT) from the set upstream optical path (Step 113), and measures thedeterioration of the optical test signal from the optical node device #3and reports the measurement result (RESULT) to the optical node device#3 (Step 114). Since no deterioration is shown in the optical testsignal from the optical node device #3 (Step 115), the optical nodedevice #1 sets an optical path to the optical node device #4, which isthree hops ahead of the optical node device #1 itself (Step 116 and Step112). In FIG. 58, the optical node device #1 sends the optical pathsetting request (PATH) to the optical node device #4 via the opticalnode devices #2 and #3. When the optical node device #4 receives theoptical path setting request (PATH), it ensures the resources requiredfor optical path setting and sends the optical path setting completionnotification (RESV) to the optical node device #1 via the optical nodedevices #3 and #2. Accordingly, the optical path is set between theoptical node devices #1 and #4.

Subsequently, the optical node device #1 receives an optical test signal(LIGHT) from the set upstream optical path (Step 113), and measures thedeterioration of the optical test signal from the optical node device #4and reports the measurement result (RESULT) to the optical node device#4 (Step 114). Since no deterioration is shown in the optical testsignal from the optical node device #4 (Step 115), the optical nodedevice #1 sets an optical path to the optical node device #5, which isfour hops ahead of the optical node device #1 itself (Step 116 and Step112). In FIG. 58, the optical node device #1 sends the optical pathsetting request (PATH) to the optical node device #5 via the opticalnode devices #2, #3, and #4. When the optical node device #5 receivesthe optical path setting request (PATH), it ensures the resourcesrequired for optical path setting and sends the optical path settingcompletion notification (RESV) to the optical node device #1 via theoptical node devices #4, #3, and #2. Accordingly, the optical path isset between the optical node devices #1 and #5.

Subsequently, the optical node device #1 receives an optical test signal(LIGHT) from the set upstream optical path (Step 113), and measures thedeterioration of the optical test signal from the optical node device #5and reports the measurement result (RESULT) to the optical node device#5 (Step 114). Since no deterioration is shown in the optical testsignal from the optical node device #5 (Step 115), the optical nodedevice #1 sets an optical path to the optical node device #6, which isfive hops ahead of the optical node device #1 itself (Step 116 and Step112). In FIG. 58, the optical node device #1 sends the optical pathsetting request (PATH) to the optical node device #6 via the opticalnode devices #2, #3, #4, and #5. When the optical node device #6receives the optical path setting request (PATH), it ensures theresources required for optical path setting and sends the optical pathsetting completion notification (RESV) to the optical node device #1 viathe optical node devices #5, #4, #3, and #2. Accordingly, the opticalpath is set between the optical node devices #1 and #6.

Subsequently, the optical node device #1 receives an optical test signal(LIGHT) from the set upstream optical path (Step 113), and measures thedeterioration of the optical test signal from the optical node device #6and reports the measurement result (RESULT) to the optical node device#6 (Step 114). Deterioration is shown in the optical test signal fromthe optical node device #6 (Step 115), so the optical node device #1requests the optical node device #5, which is four hops ahead of theoptical node device #1 itself to implement the 3R relay (Step 117). Whenthe optical node device #5 receives the request to implement the 3Rrelay from the optical node device #1, it sends an approval with respectto the request to the optical node device #1.

Moreover, the optical node device #5, in response to the notificationfrom the optical node device #1 (Step 118), recognizes that the opticalnode device #5 itself is the 3R source node, and executes the procedurefrom Step 111. Furthermore, the process is terminated since the opticalnode device #1 requests the optical node device #5 to implement the 3Rrelay, and the optical node device #1 does not receive the 3R relayimplementation request from another optical node device.

In this way, in the nineteenth embodiment, it is possible to determinethe optical node device for implementing the 3R relay in the process ofthe optical path setting. In the example of FIG. 58, all of therespective optical node devices #1 to #7 comprise a 3R relayimplementation determining unit 229. However the configuration may besuch that for example every other optical node device comprises it.Moreover, in the present embodiment, in order to facilitate description,the optical test signal was sent to the optical node device #2 or #3which is not expected to require the 3R relay. However, the sendingprocedure of the optical test signal may be omitted with respect tothese optical node devices #2 and #3. Alternatively, the optical testsignal may be sent to only the optical node device #5 or #6 which isexpected to require the 3R relay.

Twentieth Embodiment

Optical node devices according to a twentieth embodiment are describedwith reference to FIG. 60 to FIG. 63. FIG. 60 and FIG. 62 show conceptsof 3R section information collection in the optical node devicesaccording to the twentieth embodiment. FIG. 61 and FIG. 63 are blockdiagrams of the optical node devices according to the twentiethembodiment.

As shown in FIG. 61, the optical node device according to the twentiethembodiment comprises: a Q-value storing unit 234 which stores a value Q,preset for each link based on the optical signal deteriorationcharacteristic in the link between the optical node device itself andthe adjacent node; a P-value sending unit 232 which transmits theinitial value P of the minuend value to the next-hop adjacent opticalnode device if the optical node device itself is the source node; aQ-value subtraction unit 235 which calculates (P−Q) or (P′−Q) if theoptical node device itself receives the initial value P or the minuendvalue P′ which has already been reduced from the initial value P fromthe previous-hop adjacent optical node device; and a comparison unit 236which compares the calculation result by this Q-value subtraction unit235 with a threshold, then transmits the calculation result to thenext-hop adjacent optical node device if the calculation result isgreater than the threshold, or sends an instruction to implement the 3Rrelay of an optical signal that reaches the optical node device itselfif the calculation result is less than or equal to the threshold, andthe P-value sending unit 232 transmits the initial value P of theminuend value to the next-hop adjacent optical node device using theoptical node device itself as the 3R source node if the optical nodedevice itself is not the destination node of the optical path on whichthe minuend value is transmitted.

Next is a description of the operation of the optical node deviceaccording to the twentieth embodiment. The Q-value generation unit 233generates a Q-value based on the result for the degree of optical signaldeterioration of the link connected to the optical node device itself,with reference to a parameter table 240 and a degree of deteriorationtable 250. The Q-value is a constant which is determined in proportionto the degree of deterioration, and is provided for each link. Moreover,the Q-value is set with respect to the initial value P. For example, ifthe degree of optical signal deterioration of the optical node deviceitself is considered using the optical signal intensity and the lightnoise, in the case where the optical signal sent from the 3R source nodeis attenuated to half intensity and the error rate of the optical signalsent from the 3R source node is increased to double, the Q-value is setto 50 if the initial value P is 100. This Q-value is subtracted at eachtime of passing through the optical node device, and it is found thatthe optical node device having the subtraction result less than or equalto the threshold implements the 3R relay. Furthermore, if the opticalnode device itself is not the destination node of the measured opticalpath, the optical node device defines the optical node device itself asthe 3R source node, and newly send the initial value P.

In this manner, the 3R relay implementation can be determined in theprocess of optical path setting. That is, if the initial value P isloaded into the optical path setting request, the optical path settingprocedure can be executed while determining whether or not the opticalnode device itself implements the 3R relay in the respective opticalnode devices which receive the optical path setting request.

The twentieth embodiment up to here is described on the assumption of adownstream optical path of the unidirectional optical path or thebi-directional optical path. The following is a description on theassumption of the upstream optical path, with reference to FIG. 62 andFIG. 63. As shown in FIG. 63, the optical node device according to thetwentieth embodiment comprises: a q-value storing unit 334 which storesa value q, preset for each link based on the optical signaldeterioration characteristic in the link between the optical node deviceitself and the adjacent node; a p-value sending unit 332 which transmitsthe initial value p of the augend to the next-hop adjacent optical nodedevice if the optical node device itself is the source node; a q-valueaddition unit 335 which calculates (p+q) or (p′+q) if the optical nodedevice itself receives the initial value p or the augend value p′, whichhas already been increased from the initial value p, from theprevious-hop adjacent optical node device; and a comparison unit 336which compares the calculation result by this q-value addition unit 335with the threshold, then transmits the calculation result to thenext-hop adjacent optical node device if the calculation result is lessthan the threshold, or sends an instruction to implement the 3R relay ofan optical signal in the upstream optical path that reaches the opticalnode device itself if the calculation result is greater than or equal tothe threshold, wherein the p-value sending unit 332 transmits theinitial value p of the augend to the next-hop adjacent optical nodedevice using the optical node device itself as the 3R destination nodeon the upstream optical path if the optical node device itself is notthe destination node of the optical path on which the augend istransmitted.

Next is a description of the operation of the optical node deviceaccording to the twentieth embodiment. The q-value generation unit 333generates a q-value based on the result for the degree of optical signaldeterioration of the link connected to the optical node device itself,with reference to the parameter table 240 and the degree ofdeterioration table 250. The q-value is a constant which is determinedin proportion to the degree of deterioration, and is provided for eachlink. Moreover, the q-value is set similarly to the case of the Q-valueof the downstream optical path.

This q-value is added at each time of passing through the optical nodedevice, and it is found that the optical node device having the additionresult greater than or equal to the threshold implements the 3R relay onthe upstream optical path. Furthermore, if the optical node deviceitself is not the destination node of the measured optical path, theoptical node device defines the optical node device itself as the 3Rdestination node on the upstream optical path, and newly sends theinitial value p. The p value is “0” in the twentieth embodiment; howeverthe p-value may be set in consideration of various conditions. Forexample, the length of the 3R section to be set can be adjusted by thep-value within a range of the maximum length of the 3R section. That is,if the threshold is fixed, assuming that the p-value is a negativeinteger, the value capable of being added is increased more than in thecase where the p-value is set to “0”, enabling the 3R section to be setlonger. Conversely, assuming that the p-value is a positive integer, thevalue capable of being added is decreased more than in the case wherethe p-value is set to “0”, enabling the 3R section to be set shorter.

In this manner, the 3R relay implementation can be determined in theprocess of optical path setting. That is, if the initial value p isloaded into the optical path setting request, the optical path settingprocedure can be executed while determining whether or not the opticalnode device itself implements the 3R relay in the respective opticalnode devices which receive the optical path setting request.

In the seventeenth to twentieth embodiments, in order to facilitatedescription, the case on the assumption of the downstream optical pathand the case on the assumption of the upstream optical path weredescribed separately. However, in practice, by performing them at thesame time, the 3R section can be set both on the upstream and downstreambi-directional optical paths at the same time.

Twenty-first Embodiment

A twenty-first embodiment according to the present invention isdescribed with reference to FIG. 64 to FIG. 66. FIG. 64 shows therelation of a network control device and an optical network in thetwenty-first embodiment. FIG. 65 is a block diagram of the networkcontrol device according to the twenty-first embodiment. FIG. 66 is ablock diagram of a maintenance-staff device according to thetwenty-first embodiment.

As shown in FIG. 64, the twenty-first embodiment is a network controldevice 410 which manages an optical network comprising a plurality ofoptical node devices 1 to 8 which switch the optical signal, and opticaltransmission paths which connect between this plurality of optical nodedevices 1 to 8. Here, as shown in FIG. 65, the twenty-first embodimentcomprises: a topology information storing unit 411 which stores thetopology information of the optical network; a 3R section informationgeneration unit 412 which generates in the topology information,estimate information of a 3R section in which an optical node devicespecified is a 3R source node, based on input information of the numberof hops; a 3R section information modification unit 413 which modifies apart or all of the 3R section estimate information in the topologyinformation that was generated by this 3R section information generationunit 412, based on the input instruction; and a 3R section informationnotification unit 414 which notifies the information of the 3R sectionin the topology information that was modified by this 3R sectioninformation modification unit 413, to the optical node devices.

Next is a description of the operation of the network control device 410according to the twenty-first embodiment. As shown in FIG. 64, thenetwork control device 410 integrally manages the optical networkcomprising the optical node devices 1 to 8. That is, the respectiveoptical node devices 1 to 8 communicate with the network control device410, so that they recognize a role which has been assigned to theoptical node device itself on the optical network, and activate thefunction corresponding to the role. Moreover, the network control device410 aggregates and stores various information from the respectiveoptical node devices 1 to 8, and executes various calculations andprocessing required for the optical network management, based on theaggregated information.

Here is a description of an embodiment where the network control device410 generates the 3R section information. The topology informationstoring unit 411 stores the topology information of the optical networkshown in FIG. 64. The information is updated at regular intervals.Alternatively, it is updated at each time when the topology is modified.Subsequently, the 3R section estimate information using the optical nodedevice specified based on input information of the number of hops as the3R source node, is generated in this topology information. In theexample of FIG. 65, the information of the number of hops is “2” and the3R source node is the optical node device 1.

Accordingly, the estimated information for three 3R sections of 1->2->3,1->4->6, and 1->5->7 is generated in the topology information of the 3Rsection information generation unit 412. Subsequently, the modifiedinformation of the 3R section estimate information which is desired tobe modified is input into the 3R section information modification unit413. In the example of FIG. 64, an instruction to modify the 3R sectionfrom 1->5->7 to 1->5->7->8 is input. Such instruction to modify isperformed in a case where a user who frequently uses the section1->5->7->8 confirms by measurement, that the section 1->5->7->8 is the3R section.

The 3R section information modified in such manner is notified to therespective optical node devices 1 to 8 by the 3R section informationnotification unit 414. This notification may be performed at each timewhen the 3R section information is modified, or the respective opticalnode devices 1 to 8 may request the notification from the networkcontrol device 410 as necessary.

Here is a description of a method of determining the information of thenumber of hops input into the 3R section information generation unit412. The information of the number of hops is determined by estimatingthe 3R section and the number of hops thereof. However, amaintenance-staff device which has a function of automaticallycalculating the information of the number of hops is described in thetwenty-first embodiment.

As shown in FIG. 66, the maintenance-staff device according to thetwenty-first embodiment comprises: an information of the number of hopsgeneration unit 445 which generates the information on the number ofhops; a parameter table 440 which stores the topology information of theoptical network together with the information on the optical fiber typeand the wavelength band used in the optical network; and a degree ofdeterioration table 450 which records the relation between the opticalfiber type and the wavelength band, and the degree of optical signaldeterioration per unit section, wherein the information of the number ofhops generation unit 445 compares the information on the optical fibertype and the wavelength band in the topology information obtained withreference to the parameter table 440, with the optical fiber type andthe wavelength band and the degree of optical signal deterioration perunit section recorded in the degree of deterioration table 450, andgenerates the information on the number of hops.

Next is a description of the operation of the maintenance-staff deviceaccording to the twenty-first embodiment. The information of the numberof hops generation unit 445 refers to the topology information toestimate the 3R section, using for example the optical node device 1 asthe 3R source node. The parameter table 440 and the degree ofdeterioration table 450 are used for this estimation.

Here is a description of the estimating procedure of the information ofthe number of hops if the optical node device 1 is the 3R source node.Assuming that an optical path is set from the optical node device 1 tothe optical node device 4, then from the parameter table 440, theoptical fiber type where the optical path is set is D, and thewavelength band is L. Next, the degree of deterioration of a combinationof the optical fiber type D and the wavelength band L is examined withreference to the degree of deterioration table 450. The result is “−1”.

Subsequently, assuming that an optical path is set from the optical nodedevice 4 to the optical node device 6, then from the parameter table440, the optical fiber type where the optical path is set is B and thewavelength band is L. Next, the degree of deterioration of a combinationof the optical fiber type B and the wavelength band L is examined withreference to the degree of deterioration table 450. The result is “−4”.From these results, the degree of deterioration from the optical nodedevice 1 to the optical node device 6 is “−5”.

Subsequently, assuming that an optical path is set from the optical nodedevice 6 to the optical node device 8, then from the parameter table440, the optical fiber type where the optical path is set is C and thewavelength band is L. Next, the degree of deterioration of a combinationof the optical fiber type C and the wavelength band L is examined withreference to the degree of deterioration table 450. The result is “−2”.From these results, the degree of deterioration from the optical nodedevice 1 to the optical node device 8 is “−7”.

Here, for example if it is apparent that the 3R relay is not requiredfor the degree of deterioration up to “−5”, it becomes apparent that the3R relay is not required for the optical node device up to 1->4->6. Fromthe result obtained in this manner, the number of hops of the 3R sectionis estimated and it is given to the 3R section information generationunit 412 of the network control device 410.

The twenty-first embodiment up to here is described on the assumption ofa downstream optical path of the unidirectional optical path or thebi-directional optical path. Since it can be readily inferred that the3R section information of the upstream optical path can be generated ina similar procedure to that of the downstream optical path, detaileddescription is omitted.

Twenty-second Embodiment

A twenty-second embodiment is described with reference to FIG. 51 thatwas referred to in the seventeenth embodiment, and to FIG. 67 to FIG.70. FIG. 67 and FIG. 69 are block diagrams of the network control deviceaccording to the twenty-second embodiment. FIG. 68 and FIG. 70 areexplanatory diagrams of an optical node device which measures based onan instruction from the network control device according to thetwenty-second embodiment. The block diagram of the measuring unit of thepresent embodiment is similar to that of FIG. 51.

As shown in FIG. 67, a network control device 410 according to thetwenty-second embodiment comprises: a topology information storing unit411 which stores the topology information of the optical network; a 3Rsection information generation unit 412 which generates in the topologyinformation, estimate information of a 3R section in which an opticalnode device 1 specified is the 3R source node based on input informationof the number of hops; an optical test path setting unit 415 whichinstructs the optical node devices 1 to 8 to set optical test paths onthe section in the optical network corresponding to the 3R sectionestimate information in the topology information that was generated bythis 3R section information generation unit 412; a measured datacollection unit 416 which collects the measurement results of the degreeof optical signal deterioration in the optical test path set by thisoptical test path setting unit 415 of the optical node devices 1 to 8; a3R section information modification unit 413 which modifies a part orall of the 3R section estimate information in the topology informationthat was generated by the 3R section information generation unit 412,based on the measurement result of the degree of optical signaldeterioration collected by this measured data collection unit 416; and a3R section information notification unit 414 which notifies theinformation of the 3R section in the topology information that wasmodified by this 3R section information modification unit 413, to theoptical node devices 1 to 8.

Next is a description of the operation of the network control device 410according to the twenty-second embodiment. As shown in FIG. 64, thenetwork control device 410 integrally manages the optical networkcomprising the optical node devices 1 to 8. That is, the respectiveoptical node devices 1 to 8 communicate with the network control device410, so that they recognize a role which has been assigned to theoptical node device itself on the optical network, and activate thefunction corresponding to the role. Moreover, the network control device410 aggregates and stores various information from the respectiveoptical node devices 1 to 8, and executes various calculations andprocessing required for the optical network management, based on theaggregated information.

Here is a description of an embodiment where the network control device410 generates the 3R section information. The topology informationstoring unit 411 stores the topology information of the optical networkshown in FIG. 64. The information is updated at regular intervals.Alternatively, it is updated at each time when the topology is modified.Subsequently, the 3R section estimate information using the optical nodedevice specified based on input information of the number of hops as the3R source node, is generated in this topology information. In theexample of FIG. 67, the information of the number of hops is “3” and the3R source node is the optical node device 1.

Accordingly, the estimated information for three 3R sections of 1->2->3,1->4->6->8, and 1->5->7->8 is generated in the topology information ofthe 3R section information generation unit 412. Subsequently, theoptical test path setting unit 415 instructs the optical node devices 1to 8 to actually set the optical test path on the 3R section generatedby the 3R section information generation unit 412, so as to measure.

The 3R section measuring procedure in the optical node devices 1, 4, 6,and 8 is described with reference to FIG. 68. When an instruction fromthe optical test path setting unit 415 arrives at the control system 417of the respective optical node devices 1, 4, 6, or 8, the respectiveoptical node devices 1, 4, 6, or 8 recognize their own role and activatetheir functions. That is, the optical node device 1 recognizes that theoptical node device 1 itself is the 3R source node and sets the opticaltest path up to the optical node device 8, ensures the resourcesrequired for optical test path setting up to the adjacent optical nodedevice 4, and sends an optical test path setting request to the opticalnode device 4. The optical node device 4 receives the optical test pathsetting request from the optical node device 1, ensures the resourcesrequired for optical test path setting up to the adjacent optical nodedevice 6, and sends the optical test path setting request to the opticalnode device 6. The optical node device 6 receives the optical test pathsetting request from the optical node device 4, ensures the resourcesrequired for optical test path setting up to the adjacent optical nodedevice 8, and sends the optical test path setting request to the opticalnode device 8. The optical node device 8 receives the optical test pathsetting request from the optical node device 6, performs the opticaltest path setting between the optical node device 6, and sends anoptical test path setting completion notification for notifying thecompletion of the setting to the optical node device 6. The optical nodedevice 6 receives the optical test path setting completion notificationfrom the optical node device 8, performs the optical test path settingbetween the optical node device 4, and sends the optical test pathsetting completion notification for notifying the completion of thesetting to the optical node device 4. The optical node device 4 receivesthe optical test path setting completion notification from the opticalnode device 6, performs the optical test path setting between theoptical node device 1, and sends the optical test path settingcompletion notification for notifying the completion of the setting tothe optical node device 1. These optical test path settings areperformed by the optical path setting unit 419.

The optical node device 1 receives the optical test path settingcompletion notification from the optical node device 4, recognizes thatthe optical test path was set up to the optical node device 8, and sendsan optical test signal from the transmitter (TX) of the measuring unit418 to the optical test path. This optical test signal is received bythe receiver (RX) of the measuring units 418 of the respective opticalnode devices 4, 6, and 8. The measuring unit 418 of the respectiveoptical node devices 4, 6, and 8 which receive the optical test signaldetermines the degree of deterioration of the optical test signal andnotifies the result to the control system 417 of the optical node device1. The control system 417 of the optical node device 1 which receivesthese notifications recognizes that the 3R relay is not required up tothe optical node devices 4 and 6, and notifies the measurement result tothe network control device 410. The optical node device 1 also measuresthe section 1->2->3 and the section 1->5->7->8 in a similar manner.

As described with reference to FIG. 51, the measuring unit 418 measuresthe light noise of the optical signal by a light noise observation unit225, and the light intensity of the optical signal by a light intensityobservation unit 226. This measurement result is aggregated by ameasured data generation unit 231. The measuring unit 418 in otherembodiments has a similar configuration.

The measured data collection unit 416 of the network control device 410collects the measurement result notified from the optical node device 1,and transmits it to the 3R section information modification unit 413.The 3R section information modification unit 413 modifies the 3R sectionestimate information generated by the 3R section information generationunit 412, based on the measurement result transmitted from the measureddata collection unit 416. As a result, the 3R section 1->4->6->8 ismodified into 1->4->6. The 3R section information modified by the 3Rsection information modification unit 413 is notified to the respectiveoptical node devices 1 to 8 by the 3R section information notificationunit 414. This notification may be performed at each time when the 3Rsection information is modified, or the respective optical node devices1 to 8 may request the notification from the network control device 410as necessary.

The twenty-second embodiment up to here is described on the assumptionof a downstream optical path of the unidirectional optical path or thebi-directional optical path. The following is a description on theassumption of the upstream optical path, with reference to FIG. 69 andFIG. 70. As shown in FIG. 64, the network control device 410 integrallymanages the optical network comprising the optical node devices 1 to 8.That is, the respective optical node devices 1 to 8 communicate with thenetwork control device 410, so that they recognize a role which has beenassigned to the optical node device itself on the optical network, andactivate the function corresponding to the role. Moreover, the networkcontrol device 410 aggregates and stores various information from therespective optical node devices 1 to 8, and executes variouscalculations and processing required for the optical network management,based on the aggregated information.

Here is a description of an embodiment where the network control device410 generates the 3R section information. The topology informationstoring unit 411 stores the topology information of the optical networkshown in FIG. 64. The information is updated at regular intervals.Alternatively, it is updated at each time when the topology is modified.Subsequently, the 3R section estimate information using the optical nodedevice specified based on input information of the number of hops as the3R source node, is generated in this topology information. In theexample of FIG. 69, the information of the number of hops is “3” and the3R source nodes are the optical node devices 3 and 8.

Accordingly, the estimated information for three 3R sections of 3->2->1,8->6->4->1, and 8->7->5->1 is generated on the topology information ofthe 3R section information generation unit 412. Subsequently, theoptical test path setting unit 415 instructs the optical node devices 1to 8 to actually set the optical test paths on the 3R sections generatedby the 3R section information generation unit 412, so as to measure.

The 3R section measuring procedure in the optical node devices 1, 4, 6,and 8 is described with reference to FIG. 70. When an instruction fromthe optical test path setting unit 415 arrives at the control system 417of the respective optical node devices 1, 4, 6, or 8, the respectiveoptical node devices 1, 4, 6, or 8 recognize their own role and activatetheir functions. That is, the optical node device 1 recognizes that theoptical node device 1 itself is the 3R destination node on the upstreamoptical path and sets the optical test path up to the optical nodedevice 8, ensures the resources required for optical test path settingup to the adjacent optical node device 4, and sends an optical test pathsetting request to the optical node device 4. The optical node device 4receives the optical test path setting request from the optical nodedevice 1, ensures the resources required for optical test path settingup to the adjacent optical node device 6, and sends the optical testpath setting request to the optical node device 6. The optical nodedevice 6 receives the optical test path setting request from the opticalnode device 4, ensures the resources required for optical test pathsetting up to the optical node device 8, and sends the optical test pathsetting request to the optical node device 8. The optical node device 8receives the optical test path setting request from the optical nodedevice 6, performs the optical test path setting between the opticalnode device 6, and sends an optical test path setting completionnotification for notifying the completion of the setting to the opticalnode device 6. The optical node device 6 receives the optical test pathsetting completion notification from the optical node device 8, performsthe optical test path setting between the optical node device 4, andsends the optical test path setting completion notification fornotifying the completion of the setting to the optical node device 4.The optical node device 4 receives the optical test path settingcompletion notification from the optical node device 6, performs theoptical test path setting between the optical node device 1, and sendsthe optical test path setting completion notification for notifying thecompletion of the setting to the optical node device 1. These opticaltest path settings are performed by the optical path setting unit 419.

The optical node device 1 receives the optical test path settingcompletion notification from the optical node device 4, and recognizesthat the optical test path was set up to the optical node device 8.Subsequently, the optical node device 1 requests the optical node device8 to send an optical test signal. The optical node device 8 whichreceives this request sends the optical test signal from the transmitter(TX) of the measuring unit 418 to the upstream optical test path. Thisoptical test signal is received by the receiver (RX) of the measuringunits 418 of the respective optical node devices 6, 4, and 1. Themeasuring unit 418 of the respective optical node devices 6 and 4 whichreceive the optical test signal determines the degree of deteriorationof the optical test signal and notifies the result to the control system417 of the optical node device 1. The control system 417 of the opticalnode device 1 which receives these notifications recognizes that the 3Rrelay is not required for the optical node devices 4 and 6 but isrequired for the optical node device 1 due to a lot of deterioration inthe optical test signal received by itself (optical node device 1), andnotifies the measurement result to the network control device 410. Theoptical node device 1 also measures the section 3->2->1 and the section8->7->5->1 in a similar manner.

The measured data collection unit 416 of the network control device 410collects the measurement result notified from the optical node device 1,and transmits it to the 3R section information modification unit 413.The 3R section information modification unit 413 modifies the 3R sectionestimate information generated by the 3R section information generationunit 412, based on the measurement result transmitted from the measureddata collection unit 416. As a result, the 3R section 8->6->4->1 ismodified into 6->4->1. The 3R section information modified by the 3Rsection information modification unit 413 is notified to the respectiveoptical node devices 1 to 8 by the 3R section information notificationunit 414. This notification may be performed at each time when the 3Rsection information is modified, or the respective optical node devices1 to 8 may request the notification from the network control device 410as necessary.

In this manner, the network control device 410 of the twenty-secondembodiment measures the estimate value of the number of hops which wasinitially given to the 3R section information generation unit 412, andmodifies it, so that accurate 3R section information can be obtainedeventually. Therefore, a maximum value estimated as possible for the 3Rsection is desirably given as the estimate value of the number of hopsto give to the 3R section information generation unit 412.Alternatively, the number of hops slightly exceeding the maximum valuemay be given, in anticipation of amendment by measurement. Accordingly,a 3R section as large as possible can be set on the optical network, sothat it is possible to constitute an economical optical network byeffectively using network resources by using the minimum number of, orminimum capacity of, the 3R repeater.

Twenty-third Embodiment

A twenty-third embodiment is described with reference to FIG. 71 andFIG. 72. FIG. 71 is a schematic block diagram of a network controldevice according to the twenty-third embodiment. FIG. 72 is anexplanatory diagram of traffic demand information collection in thenetwork control device according to the twenty-third embodiment.

As shown in FIG. 71, a network control device 410 according to thetwenty-third embodiment comprises: a topology information storing unit411 which stores the topology information of the optical network; a 3Rsection information storing unit 420 which stores a 3R section set inthe optical network, corresponding to the topology information; atraffic demand information collection unit 421 which collects thetraffic demand information in the optical network; and an additional 3Rsection information request unit 422 which refers to the information ofthe 3R section information storing unit 420, based on the traffic demandinformation collected by this traffic demand information collection unit421, to notify the section not having 3R section information generatedyet among the sections having the traffic demand increased, to themaintenance-staff.

Next is a description of the operation of the network control device 410according to the twenty-third embodiment. The network control device 410according to the twenty-third embodiment stores the 3R sectioninformation on the optical network that is already obtained in the 3Rsection information storing unit 420. The respective optical node device1 to 8 measure the traffic in links connected to the optical nodedevices themselves. The traffic demand information collection unit 421collects the traffic demand information in links connected to therespective optical node devices 1 to 8 notified by the optical nodedevices 1 to 8. Since the traffic measurement for the respective opticalnode devices 1 to 8 is a well-known technique, detailed description isomitted. This traffic demand information is transmitted to theadditional 3R section information request unit 422.

Now, as shown in FIG. 72, if the additional 3R section informationrequest unit 422 detects that the traffic demand in a section 1->4->5 isincreased, it refers to the 3R section information storing unit 420.Then, when it becomes apparent that there is no 3R section informationof the section 1->4->5, the additional 3R section information requestunit 422 requests the 3R section information of the section 1->4->5 fromthe maintenance-staff. The maintenance-staff who receive this requestgenerate the 3R section information using the function of the networkcontrol device described for embodiment in the twenty-first embodimentor the twenty-second embodiment.

The twenty-third embodiment up to here is described on the assumption ofa downstream optical path of the unidirectional optical path or thebi-directional optical path. Since it can be readily inferred that the3R section information of the upstream optical path can be generated ina similar procedure to that of the downstream optical path, detaileddescription is omitted.

Twenty-fourth Embodiment

A network control device according to a twenty-fourth embodiment isdescribed with reference to FIG. 72 and FIG. 73. FIG. 72 is anexplanatory diagram of traffic demand information collection in thenetwork control device according to the twenty-fourth embodiment, usedin common with the twenty-third embodiment. FIG. 73 is a schematic blockdiagram of a network control device according to the twenty-fourthembodiment.

As shown in FIG. 73, a network control device 410 according to thetwenty-fourth embodiment comprises: a topology information storing unit411 which stores the topology information of the optical network; a 3Rsection information storing unit 420 which stores a 3R section set inthe optical network, corresponding to the topology information; atraffic demand information collection unit 421 which collects thetraffic demand information in the optical network; an optical test pathsetting unit 415 which refers to the information of the 3R sectioninformation storing unit 420, based on the traffic demand informationcollected by this traffic demand information collection unit 421, tonewly generate the 3R section information of the section not having 3Rsection information generated yet among the sections having the trafficdemand increased; a measured data collection unit 416; and a 3R sectioninformation modification unit 413.

Next is a description of the operation of the network control device 410according to the twenty-fourth embodiment. The network control device410 according to the twenty-fourth embodiment stores the 3R sectioninformation on the optical network that is already obtained in the 3Rsection information storing unit 420. The respective optical node device1 to 8 measure the traffic in links connected to the optical nodedevices themselves. The traffic demand information collection unit 421collects the traffic demand information in links connected to therespective optical node devices 1 to 8 notified by the optical nodedevice 1 to 8. Since the traffic measurement for the respective opticalnode devices 1 to 8 is a well-known technique, detailed description isomitted. This traffic demand information is transmitted to the opticaltest path setting unit 415.

Now, as shown in FIG. 72, if the optical test path setting unit 415detects that the traffic demand in a section 1->4->5 is increased, itrefers to the 3R section information storing unit 420. Then, when itbecomes apparent that there is no 3R section information of the section1->4->5, the optical test path setting unit 415 instructs the opticalnode devices 1, 4, and 5 to set the optical test path and to measure the3R section information. The measured data collection unit 416 collectsthe measurement result of the 3R section information from the opticalnode devices 1, 4, and 5. If the measurement result shows that it ispossible to use the section 1->4->5 as the 3R section, the 3R sectioninformation modification unit 413 is instructed to use the section1->4->5 as a new 3R section. When the 3R section informationmodification unit 413 receives the instruction, it modifies the 3Rsection information, instructs the 3R section information storing unit420 to modify the 3R section information, and transmits the modifiedcontents to the 3R section information notification unit 414. The 3Rsection information notification unit 414 notifies the modified contentsto the respective optical node devices 1 to 8.

The twenty-fourth embodiment up to here is described on the assumptionof a downstream optical path of the unidirectional optical path or thebi-directional optical path. Since it can be readily inferred that the3R section information of the upstream optical path can be generated ina similar procedure to that of the downstream optical path, detaileddescription is omitted.

Twenty-fifth Embodiment

Optical node devices according to a twenty-fifth embodiment aredescribed with reference to FIG. 74 and FIG. 75. FIG. 74 and FIG. 75 areexplanatory diagrams of the schematic block configuration and theoperation of optical node devices according to the twenty-fifthembodiment. As shown in FIG. 74, the optical node device according tothe twenty-fifth embodiment comprises: a measuring unit 418 whichdetects the deterioration state of the optical signal arriving at theoptical node device itself; a control system 417 which notifies that theoptical node device is the 3R destination node and the 3R source node ofthe next 3R section, to an adjacent optical node device one hop beforethe optical node device itself when the detection result of thismeasuring unit 418 shows signal deterioration; a 3R relay unit 424 whichrecognizes that the optical node device itself is the 3R destinationnode and the 3R source node of the next 3R section when the optical nodedevice itself receives the notification from the control system 417 ofthe next-hop adjacent optical node device; and a 3R section informationstoring unit 423 which updates the 3R section information stored by the3R section information storing unit 423 itself based on the recognitionresult.

Next is a description of the operation of the optical node deviceaccording to the twenty-fifth embodiment. The optical node deviceaccording to the twenty-fifth embodiment stores the 3R sectioninformation of the whole optical network in the 3R section informationstoring unit 423, by mutual advertisement between the optical nodedevices. Moreover, if an optical path passing through the optical nodedevice itself is set, the optical node device branches and inputs theoptical signal transmitted on this optical path into the measuring unit418, and observes the signal deterioration state. Now, if optical signaldeterioration is detected in the optical node device #4, the opticalnode device #4 notifies that the optical node device #3 is the 3Rdestination node and the 3R source node of the next 3R section, to theoptical node device #3. The optical node device #3 which receives thisnotification leads the optical path passing through the optical nodedevice #3 itself to the 3R relay unit 424, and implements the 3R relay.Furthermore, the control system 417 of the optical node device #3advertises that the optical node device #3 itself is the 3R destinationnode and the 3R source node of the next 3R section, to the other opticalnode devices. The 3R section information storing unit 423 of an opticalnode device which receives the advertisement updates the 3R sectioninformation stored by this optical node device itself.

The twenty-fifth embodiment up to here is described on the assumption ofa downstream optical path of the unidirectional optical path or thebi-directional optical path. The following is a description on theassumption of the upstream optical path, with reference to FIG. 75. Asshown in FIG. 75, the optical node device according to the twenty-fifthembodiment comprises: a measuring unit 418 which detects thedeterioration state of the optical signal of the upstream optical patharriving at the optical node device itself; a control system 417 whichnotifies that the optical node device is the 3R destination node and the3R source node of the next 3R section on the upstream optical path, toan adjacent optical node device corresponding to the next-hop to theoptical node device itself when the detection result of this measuringunit 418 shows signal deterioration; a 3R relay unit 424 whichrecognizes that the optical node device itself is the 3R destinationnode and the 3R source node of the next 3R section on the upstreamoptical path when this optical node device itself receives thenotification from the control system 417 of the previous-hop adjacentoptical node device; and a 3R section information storing unit 423 whichupdates the 3R section information stored by the 3R section informationstoring unit 423 itself based on the recognition result.

Next is a description of the operation of the optical node deviceaccording to the twenty-fifth embodiment. The optical node deviceaccording to the twenty-fifth embodiment stores the 3R sectioninformation of the whole optical network in the 3R section informationstoring unit 423, by mutual advertisement between the optical nodedevices. Moreover, if an upstream optical path passing through theoptical node device itself is set, the optical node device branches andinputs the optical signal transmitted on the upstream optical path intothe measuring unit 418, and observes the signal deterioration state.Now, if optical signal deterioration is detected in the optical nodedevice #1, the optical node device #1 notifies that the optical nodedevice #2 is the 3R destination node and the 3R source node of the next3R section on the upstream optical path, to the optical node device #2.The optical node device #2 which receives this notification leads theupstream optical path passing through the optical node device #2 itselfto the 3R relay unit 424, and implements the 3R relay. Furthermore, thecontrol system 417 of the optical node device #2 advertises that theoptical node device #2 itself is the 3R destination node and the 3Rsource node of the next 3R section, to the other optical node devices.The 3R section information storing unit 423 of an optical node devicewhich receives the advertisement updates the 3R section informationstored by the 3R section information storing unit 423 itself.

Describing the situation where the preset 3R section is changed in thisway, for example in the case where a large number of new optical pathsare set to one optical node device, there might be a case where theexisting optical path receives noise caused by cross talk or nonlineareffects due to the effect of the new optical paths. In such a case, achange occurs in the 3R section. In the twenty-fifth embodiment, it ispossible to flexibly deal with such changes of the 3R section.

If the respective optical node devices each have the 3R relay unit 424,there is concern of whether or not the network resources can beeffectively used compared to the conventional technique. However, whileconventionally all optical node devices implement the 3R relay equally,only the selected optical node device implements the 3R relay in thetwenty-fifth embodiment, and the 3R relay load is distributed to aplurality of the optical node devices, so that the network resources canbe effectively used.

That is, in most cases, it is sufficient that the 3R relay unit 424 ofthe respective optical node devices implements the 3R relay only on apart of the optical path passing through the respective optical nodedevices themselves. On the other hand, conventionally, the 3R relay unit424 of the respective optical node devices is required to implement the3R relay to all of the optical paths passing through the respectiveoptical node devices themselves. Therefore, the scale of the 3R relayunit 424 can be smaller to deal with compared to the conventionaltechnique, so that the network resources can be effectively used and thecost can be reduced.

Twenty-sixth Embodiment

An optical node device according to a twenty-sixth embodiment isdescribed with reference to FIG. 76 to FIG. 78. FIG. 76 is a blockdiagram of an optical node device comprising an optical switch unit onthe output side in the twenty-sixth embodiment. FIG. 77 is a blockdiagram of an optical node device comprising the optical switch unit onthe input side in the twenty-sixth embodiment. FIG. 78 is a blockdiagram of an optical node device comprising a trunk-type 3R relay unitin the twenty-sixth embodiment.

The optical node device according to the twenty-sixth embodimentcomprises: a measuring unit 418 which detects the deterioration state ofthe optical signal arriving at the optical node device itself; a 3Rrelay unit 424 which recognizes that the optical node device itself isthe 3R destination node and the 3R source node of the next 3R sectionwhen the detection result of this measuring unit 418 shows signaldeterioration; and a 3R section information storing unit 423 whichupdates the 3R section information stored by the 3R section informationstoring unit 423 itself based on the recognition result.

In contrast to the twenty-fifth embodiment where the optical node devicewhich detected the optical signal deterioration notifies that theoptical node device itself is the 3R destination node and the 3R sourcenode of the next 3R section, to the previous-hop optical node device ofthe optical node device itself, in the twenty-sixth embodiment theoptical node device itself which detected the optical signaldeterioration recognizes that the optical node device itself is the 3Rdestination node and the 3R source node of the next 3R section.Therefore, the degree of optical signal deterioration detected in thetwenty-sixth embodiment is a lower degree of deterioration compared tothe degree of optical signal deterioration detected in the twenty-fifthembodiment. That is, even if the degree of optical signal deteriorationin the twenty-fifth embodiment is a notable deterioration to the extentthat it can not be regenerated by the 3R relay, there is no problemsince the previous-hop optical node device implements the 3R relay. Onthe other hand, the degree of optical signal deterioration in thetwenty-sixth embodiment must be to an extent that it can be regeneratedby the 3R relay of the optical node device itself.

Next is a description of the operation of the optical node deviceaccording to the twenty-sixth embodiment. In the optical node deviceshown in FIG. 76, when the measuring unit 418 detects deterioration ofthe input optical signal, the detection result is transmitted to thecontrol system 417. The control system 417 outputs an instruction to theselector 427 and the input optical signal is connected to the 3R relayunit 424. Accordingly, the optical signal which is subjected to the 3Rrelay is input into the optical switch unit 428 via the 3R relay unit424. Moreover, the 3R section information storing unit 423 recognizesthat the optical node device itself is the 3R destination node and the3R source node of the next 3R section, and updates the 3R sectioninformation which was stored until now. The configuration may be suchthat, as described in the twenty-fifth embodiment, the updated 3Rsection information is advertised to other optical node devices.

In the optical node device shown in FIG. 77, when the measuring unit 418detects deterioration of the optical signal output from the opticalswitch unit 428, the detection result is transmitted to the controlsystem 417. The control system 417 outputs an instruction to theselector 427 and the input optical signal is connected to the 3R relayunit 424. Accordingly, the optical signal which is subjected to the 3Rrelay is output via the 3R relay unit 424. Moreover, the 3R sectioninformation storing unit 423 recognizes that the optical node deviceitself becomes the optical node device for implementing the 3R relay,and updates the 3R section information which was stored until now. Theconfiguration may be such that, as described in the twenty-fifthembodiment, the updated 3R section information is advertised to otheroptical node devices.

In the optical node device shown in FIG. 78, when the measuring unit 418detects deterioration of the input optical signal, the detection resultis transmitted to the control system 417. The control system 417 outputsan instruction to the optical switch unit 428 and the input opticalsignal is connected to the 3R relay unit 424. Accordingly, the opticalsignal which is once output from the optical switch unit 428 and then 3Rrelayed via the 3R relay unit 424, is input into the optical switch unit428 again. The optical switch unit 428 switches the 3R relayed opticalsignal to the target route. Moreover, the 3R section information storingunit 423 recognizes that the optical node device itself becomes theoptical node device for implementing the 3R relay, and updates the 3Rsection information which was stored until now. The configuration may besuch that, as described in the twenty-fifth embodiment, the updated 3Rsection information is advertised to other optical node devices.

The twenty-sixth embodiment up to here is described on the assumption ofa downstream optical path of the unidirectional optical path or thebi-directional optical path. Since it can be readily inferred that the3R section information of the upstream optical path can be generated ina similar procedure to that of the downstream optical path, detaileddescription is omitted.

That is, the optical node device comprises: the measuring unit 418 whichdetects the deterioration state of the optical signal of the upstreamoptical path arriving at the optical node device itself; the controlsystem 417 which recognizes that the optical node device itself is the3R destination node and the 3R source node of the next 3R section on theupstream optical path when the detection result of this measuring unit418 shows signal deterioration; and a 3R section information storingunit 423 which updates the 3R section information stored by the 3Rsection information storing unit 423 itself based on the recognitionresult.

Twenty-seventh Embodiment

Optical node devices according to a twenty-seventh embodiment aredescribed with reference to FIG. 79 to FIG. 82. FIG. 79 and FIG. 81 showconcepts of 3R section information collection in the optical nodedevices of the twenty-seventh embodiment. FIG. 80 and FIG. 82 show 3Rsection information collection procedures in the optical node devicesaccording to the twenty-seventh embodiment.

The optical node device according to the twenty-seventh embodiment is anoptical node device which switches the optical signal and generates the3R section information on a route from the optical node device itself tothe destination node. As shown in FIG. 79, the 3R section informationcollection unit 429 comprises: a unit which sends an optical test signalat each time when the optical path is sequentially set for the otheroptical node devices included in the route to the destination node onehop at a time from the next-hop adjacent optical node device; a unitwhich receives a report on the optical test signal deterioration statefrom another optical node device at the farthest end receiving theoptical test signal at each time when the optical test signal issequentially sent to the other optical node device included in the routeto the destination node one hop at a time from the next-hop adjacentoptical node device by this sending unit; and a unit which notifies thatanother optical node device is the 3R destination node and the 3R sourcenode of the next 3R section to the other optical node device one hopbefore the other optical node device at the farthest end, if the opticaltest signal deterioration state based on the reported result received bythis receiving unit satisfies a predetermined deterioration condition.The 3R section information collection unit 429 of the other optical nodedevice which receives the notification comprises: a unit which sends theoptical test signal at each time when the optical path is sequentiallyset for the other optical node devices included in the route to thedestination node one hop at a time from the next-hop adjacent opticalnode device; a unit which receives a report on the optical test signaldeterioration state from another optical node device at the farthest endreceiving the optical test signal at each time when the optical testsignal is sequentially sent to the other optical node device included inthe route to the destination node one hop at a time from the next-hopadjacent optical node device by this sending unit; and a unit whichnotifies that the other optical node device is the 3R destination nodeand the 3R source node of the next 3R section to the other optical nodedevice one hop before the other optical node device at the farthest endwhen the optical test signal deterioration state based on the reportedresult received by this receiving unit satisfies a predetermineddeterioration condition. In practice, each optical node device comprisesa 3R section information collection unit 429, and the above functions ofthe respective units are activated when the optical node device itselfbecomes the source node or the 3R source node.

Next is a description of the optical node device according to thetwenty-seventh embodiment. The 3R section information collectingprocedure shown in FIG. 80 is executed by the 3R section informationcollection unit 429. Here is a description of an example of a process inwhich the optical node device #1 is the 3R source node and the 3Rsection information is generated while setting the optical path. Asshown in FIG. 80, the 3R section information collection unit 429 of theoptical node device #1 sets an optical path to the optical node device#2, which is one hop ahead of the optical node device #1 itself (Step201 and Step 202). In FIG. 79, the optical node device #1 sends anoptical path setting request (PATH) to the optical node device #2. Whenthe optical node device #2 receives the optical path setting request(PATH), it ensures the resources required for optical path setting andsends the optical path setting completion notification (RESV) to theoptical node device #1. Accordingly, the optical path is set between theoptical node devices #1 and #2.

Subsequently, the optical node device #1 sends an optical test signal(LIGHT) to the set optical path (Step 203), and receives an optical testsignal deterioration state report (RESULT) from the optical node device#2 (Step 204). Since no deterioration is shown in the optical testsignal deterioration state report from the optical node device #2 (Step205), the optical node device #1 sets an optical path to the opticalnode device #3, which is two hops ahead of the optical node device #1itself (Step 206 and Step 202). In FIG. 79, the optical node device #1sends the optical path setting request (PATH) to the optical node device#3 via the optical node device #2. When the optical node device #3receives the optical path setting request (PATH), it ensures theresources required for optical path setting and sends the optical pathsetting completion notification (RESV) to the optical node device #1 viathe optical node device #2. Accordingly, the optical path is set betweenthe optical node devices #1 and #3.

Subsequently, the optical node device #1 sends an optical test signal(LIGHT) to the set optical path (Step 203), and receives an optical testsignal deterioration state report (RESULT) from the optical node device#3 (Step 204). Since no deterioration is shown in the optical testsignal deterioration state report from the optical node device #3 (Step205), the optical node device #1 sets an optical path to the opticalnode device #4, which is three hops ahead of the optical node device #1itself (Step 206 and Step 202). In FIG. 79, the optical node device #1sends the optical path setting request (PATH) to the optical node device#4 via the optical node devices #2 and #3. When the optical node device#4 receives the optical path setting request (PATH), it ensures theresources required for optical path setting and sends the optical pathsetting completion notification (RESV) to the optical node device #1 viathe optical node devices #3 and #2. Accordingly, the optical path is setbetween the optical node devices #1 and #4.

Subsequently, the optical node device #1 sends an optical test signal(LIGHT) to the set optical path (Step 203), and receives an optical testsignal deterioration state report (RESULT) from the optical node device#4 (Step 204). Since no deterioration is shown in the optical testsignal deterioration state report from the optical node device #4 (Step205), the optical node device #1 sets an optical path to the opticalnode device #5, which is four hops ahead of the optical node device #1itself (Step 206 and Step 202). In FIG. 79, the optical node device #1sends the optical path setting request (PATH) to the optical node device#5 via the optical node devices #2, #3, and #4. When the optical nodedevice #5 receives the optical path setting request (PATH), it ensuresthe resources required for optical path setting and sends the opticalpath setting completion notification (RESV) to the optical node device#1 via the optical node devices #4, #3, and #2. Accordingly, the opticalpath is set between the optical node devices #1 and #5.

Subsequently, the optical node device #1 sends an optical test signal(LIGHT) to the set optical path (Step 203), and receives an optical testsignal deterioration state report (RESULT) from the optical node device#5 (Step 204). Since no deterioration is shown in the optical testsignal deterioration state report from the optical node device #5 (Step205), the optical node device #1 sets an optical path to the opticalnode device #6, which is five hops ahead of the optical node device #1itself (Step 206 and Step 202). In FIG. 79, the optical node device #1sends the optical path setting request (PATH) to the optical node device#6 via the optical node devices #2, #3, #4, and #5. When the opticalnode device #6 receives the optical path setting request (PATH), itensures the resources required for optical path setting and sends theoptical path setting completion notification (RESV) to the optical nodedevice #1 via the optical node devices #5, #4, #3, and #2. Accordingly,the optical path is set between the optical node devices #1 and #6.

Subsequently, the optical node device #1 sends an optical test signal(LIGHT) to the set optical path (Step 203), and receives an optical testsignal deterioration state report (RESULT) from the optical node device#6 (Step 204). Deterioration is shown in the optical test signaldeterioration state report from the optical node device #6 (Step 205),so that the optical node device #1 notifies (state notification) thatthe optical node device #5 is the 3R destination node and the 3R sourcenode of the next 3R section, to the optical node device #5, which isfour hops ahead of the optical node device #1 itself (Step 207). Whenthe optical node device #5 receives the notification from the opticalnode device #1, it sends an approval that the optical node device #5itself is the 3R destination node and the 3R source node of the next 3Rsection, to the optical node device #1.

Moreover, the optical node device #5 receives the notification from theoptical node device #1 (Step 208), so that it recognizes that theoptical node device #5 itself is the 3R source node, and executes theprocedure from Step 201. Furthermore, the process is terminated sincethe optical node device #1 notifies that the optical node device #5 isthe 3R destination node and the 3R source node of the next 3R section,and the optical node device #1 does not receive notification that theoptical node device #1 is the 3R destination node and the 3R source nodeof the next 3R section from another optical node device.

In this way, in the twenty-seventh embodiment, it is possible to collectthe 3R section information while determining the optical node device forimplementing the 3R relay in the process of the optical path setting. Inthe example of FIG. 79, all of the respective optical node devices #1 to#7 comprise a 3R section information collection unit 429. However theconfiguration may be such that for example every other optical nodedevice comprises it. Moreover, in the present embodiment, in order tofacilitate description, the optical test signal was sent to the opticalnode devices #2 and #3 which are not expected to require the 3R relay.However, the sending procedure of the optical test signal may be omittedwith respect to these optical node devices #2 and #3. Alternatively, theoptical test signal may be sent to only the optical node devices #5 and#6 which are expected to require the 3R relay.

The twenty-seventh embodiment up to here is described on the assumptionof a downstream optical path of the unidirectional optical path or thebi-directional optical path. The following is a description on theassumption of the upstream optical path, with reference to FIG. 81 andFIG. 82. The optical node device according to the twenty-seventhembodiment is an optical node device which generates the 3R sectioninformation on a route from the source node to the destination node, andcomprises a 3R section information collection unit 429 whichsequentially sets the optical path one hop at a time from the next-hopadjacent optical node device to another optical node device included inthe route to the destination node, if the optical node device itself isthe source node. The 3R section information collection unit 429comprises a unit which sends an optical test signal to the upstreamoptical path when the optical path is set to the optical node deviceitself, if the optical node device itself is not the source node.Moreover, this 3R section information collection unit 429 comprises aunit which receives the optical test signal if the optical node deviceitself is the source node and notifies the report on the optical testsignal deterioration state to the sender of the optical test signal.Furthermore, the 3R section information collection unit 429 of theoptical node device of the sender of the optical test signal comprises aunit which recognizes that the optical node device itself is the 3Rsource node and the 3R destination node of the previous 3R section onthe upstream optical path, if the optical test signal deteriorationstate based on this notification satisfies a predetermined deteriorationcondition. The 3R section information collection unit 429 of the opticalnode device which recognizes that the optical node device itself is the3R source node and the 3R destination node of the previous 3R section onthe upstream optical path, comprises a unit which sequentially sets theoptical path one hop at a time from the next-hop adjacent optical nodedevice to another optical node device included in the route from theoptical node device itself to the destination node, receives the opticaltest signal, and notifies the report on the optical test signaldeterioration state to the sender of the optical test signal. Inpractice, each optical node device comprises a 3R section informationcollection unit 429, and the above functions of the respective units areactivated when the optical node device itself becomes the source node,the 3R source node, or the 3R destination node.

Next is a description of the optical node device according to thetwenty-seventh embodiment. The 3R section information collectingprocedure shown in FIG. 82 is executed by the 3R section informationcollection unit 429. Here is a description of an example of a process inwhich the optical node device #1 is the 3R destination node on theupstream optical path and the 3R section information is generated whilesetting the optical path. As shown in FIG. 82, the 3R sectioninformation collection unit 429 of the optical node device #1 sets anoptical path to the optical node device #2, which is one hop ahead ofthe optical node device #1 itself (Step 211 and Step 212). In FIG. 81,the optical node device #1 sends an optical path setting request (PATH)to the optical node device #2. When the optical node device #2 receivesthe optical path setting request (PATH), it ensures the resourcesrequired for optical path setting and sends the optical path settingcompletion notification (RESV) to the optical node device #1.Accordingly, the optical path is set between the optical node devices #1and #2.

Subsequently, the optical node device #1 receives an optical test signal(LIGHT) from the set upstream optical path (Step 213), and measures thedeterioration in the optical test signal from the optical node device #2and reports the measurement result (RESULT) to the optical node device#2 (Step 214). Since no deterioration is shown in the optical testsignal from the optical node device #2 (Step 215), the optical nodedevice #1 sets an optical path to the optical node device #3, which istwo hops ahead of the optical node device #1 itself (Step 216 and Step212). In FIG. 81, the optical node device #1 sends the optical pathsetting request (PATH) to the optical node device #3 via the opticalnode device #2. When the optical node device #3 receives the opticalpath setting request (PATH), it ensures the resources required foroptical path setting and sends the optical path setting completionnotification (RESV) to the optical node device #1 via the optical nodedevice #2. Accordingly, the optical path is set between the optical nodedevices #1 and #3.

Subsequently, the optical node device #1 receives an optical test signal(LIGHT) from the set upstream optical path (Step 213), and measures thedeterioration in the optical test signal from the optical node device #3and reports the measurement result (RESULT) to the optical node device#3 (Step 214). Since no deterioration is shown in the optical testsignal from the optical node device #3 (Step 215), the optical nodedevice #1 sets the optical path to the optical node device #4, which isthree hops ahead of the optical node device #1 itself (Step 216 and Step212). In FIG. 81, the optical node device #1 sends the optical pathsetting request (PATH) to the optical node device #4 via the opticalnode devices #2 and #3. When the optical node device #4 receives theoptical path setting request (PATH), it ensures the resources requiredfor optical path setting and sends the optical path setting completionnotification (RESV) to the optical node device #1 via the optical nodedevices #3 and #2. Accordingly, the optical path is set between theoptical node devices #1 and #4.

Subsequently, the optical node device #1 receives an optical test signal(LIGHT) from the set upstream optical path (Step 213), and measures thedeterioration in the optical test signal from the optical node device #4and reports the measurement result (RESULT) to the optical node device#4 (Step 214). Since no deterioration is shown in the optical testsignal from the optical node device #4 (Step 215), the optical nodedevice #1 sets the optical path to the optical node device #5, which isfour hops ahead of the optical node device #1 itself (Step 216 and Step212). In FIG. 81, the optical node device #1 sends the optical pathsetting request (PATH) to the optical node device #5 via the opticalnode devices #2, #3, and #4. When the optical node device #5 receivesthe optical path setting request (PATH), it ensures the resourcesrequired for optical path setting and sends the optical path settingcompletion notification (RESV) to the optical node device #1 via theoptical node devices #4, #3, and #2. Accordingly, the optical path isset between the optical node devices #1 and #5.

Subsequently, the optical node device #1 receives an optical test signal(LIGHT) from the set upstream optical path (Step 213), and measures thedeterioration in the optical test signal from the optical node device #5and reports the measurement result (RESULT) to the optical node device#5 (Step 214). Since no deterioration is shown in the optical testsignal from the optical node device #5 (Step 215), the optical nodedevice #1 sets the optical path to the optical node device #6, which isfive hops ahead of the optical node device #1 itself (Step 216 and Step212). In FIG. 81, the optical node device #1 sends the optical pathsetting request (PATH) to the optical node device #6 via the opticalnode devices #2, #3, #4, and #5. When the optical node device #6receives the optical path setting request (PATH), it ensures theresources required for optical path setting and sends the optical pathsetting completion notification (RESV) to the optical node device #1 viathe optical node devices #5, #4, #3, and #2. Accordingly, the opticalpath is set between the optical node devices #1 and #6.

Subsequently, the optical node device #1 receives an optical test signal(LIGHT) from the set upstream optical path (Step 213), and measures thedeterioration in the optical test signal from the optical node device #6and reports the measurement result (RESULT) to the optical node device#6 (Step 214). Deterioration is detected in the optical test signal fromthe optical node device #6 (Step 215), so the optical node device #1notifies (state notification) that the optical node device #5 is the 3Rsource node and the 3R destination node of the previous 3R section onthe upstream optical path, to the optical node device #5, which is fourhops ahead of the optical node device #1 itself (Step 217). When theoptical node device #5 receives the notification from the optical nodedevice #1, it sends an approval that the optical node device #5 itselfis the 3R source node and the 3R destination node of the previous 3Rsection on the upstream optical path, to the optical node device #1.

Moreover, the optical node device #5 receives the notification from theoptical node device #1 (Step 218), so that it recognizes that theoptical node device #5 itself is the 3R source node, and executes theprocedure from Step 211. Furthermore, the process is terminated sincethe optical node device #1 notifies that the optical node device #5 isthe 3R source node and the 3R destination node of the previous 3Rsection, to the optical node device #5, and the optical node device #1does not receive notification that the optical node device #1 is the 3Rsource node and the 3R destination node of the previous 3R section fromanother optical node device.

In the example of FIG. 81, when the optical node device #1 receives theoptical test signal of the optical node devices #2 to #5 arriving fromthe upstream optical path, even if deterioration is not detected, thereport is performed (RESULT). However, this report has only the role ofensuring reception confirmation of the optical test signal, so that thisreporting procedure may be omitted.

In this way, in the twenty-seventh embodiment, it is possible to collectthe 3R section information while determining the optical node device forimplementing the 3R relay in the process of the optical path setting. Inthe example of FIG. 81, all of the respective optical node devices #1 to#7 comprise a 3R section information collection unit 429. However theconfiguration may be such that for example every other optical nodedevice comprises it. Moreover, in the present embodiment, in order tofacilitate description, the optical test signal was sent to the opticalnode devices #2 and #3 which are not expected to require the 3R relay.However, the sending procedure of the optical test signal may be omittedwith respect to these optical node devices #2 and #3. Alternatively, theoptical test signal may be sent to the optical node devices #5 and #6which are expected to require the 3R relay.

Twenty-eighth Embodiment

Optical node devices according to a twenty-eighth embodiment aredescribed with reference to FIG. 83 to FIG. 86. FIG. 83 and FIG. 85 showconcepts of 3R section information collection in the optical nodedevices according to the twenty-eighth embodiment. FIG. 84 and FIG. 86show 3R section information collecting procedures in the optical nodedevices according to the twenty-eighth embodiment.

The 3R section information collection unit 430 of the optical nodedevice according to the twenty-eighth embodiment comprises: a unit whichsequentially sets an optical test path from the optical node deviceitself one hop at a time from the next-hop adjacent optical node deviceto another optical node device included in a measured link beingsubjected to the measurement of 3R section information; a unit whichsends an optical test signal at each time when the optical path issequentially set to the other optical node device included in themeasured link one hop at a time from the next-hop adjacent optical nodedevice by this setting unit; a unit which receives a report on theoptical test signal deterioration state from another optical node deviceat the farthest end receiving the optical test signal at each time whenthe optical test signal is sequentially sent to the other optical nodedevice included in the measured link one hop at a time from the next-hopadjacent optical node device by this sending unit; and a unit whichrecognizes that another optical node device one hop before the otheroptical node device at the farthest end, is the 3R destination node andthe 3R source node of the next 3R section, if the optical test signaldeterioration state based on the reported result received by thisreceiving unit satisfies a predetermined deterioration condition. Inpractice, each optical node device comprises a 3R section informationcollection unit 430, and the above functions of the respective units areactivated as required to collect the 3R section information of theoptical node device itself.

Next is a description of the optical node device according to thetwenty-eighth embodiment. The 3R section information collectingprocedure shown in FIG. 84 is executed by the 3R section informationcollection unit 430. Here is a description of an example of a process inwhich the 3R section information is collected assuming that the opticalnode device #1 is the 3R source node. As shown in FIG. 83, the 3Rsection information collection unit 430 of the optical node device #1sets an optical test path to the optical node device #2, which is onehop ahead of the optical node device #1 itself (Step 221 and Step 222).In FIG. 83, the optical node device #1 sends an optical test pathsetting request (PATH) to the optical node device #2. When the opticalnode device #2 receives the optical test path setting request (PATH), itensures the resources required for optical test path setting and sendsthe optical test path setting completion notification (RESV) to theoptical node device #1. Accordingly, the optical test path is setbetween the optical node devices #1 and #2.

Subsequently, the optical node device #1 sends an optical test signal(LIGHT) to the set optical test path (Step 223), and receives an opticaltest signal deterioration state report (RESULT) from the optical nodedevice #2 (Step 224). Since no deterioration is shown in the opticaltest signal deterioration state report from the optical node device #2(Step 225), the optical node device #1 sets an optical test path to theoptical node device #3, which is two hops ahead of the optical nodedevice #1 itself (Step 226 and Step 222). In FIG. 83, the optical nodedevice #1 sends the optical test path setting request (PATH) to theoptical node device #3 via the optical node device #2. When the opticalnode device #3 receives the optical test path setting request (PATH), itensures the resources required for optical test path setting and sendsthe optical test path setting completion notification (RESV) to theoptical node device #1 via the optical node device #2. Accordingly, theoptical test path is set between the optical node devices #1 and #3.

Subsequently, the optical node device #1 sends an optical test signal(LIGHT) to the set optical test path (Step 223), and receives an opticaltest signal deterioration state report (RESULT) from the optical nodedevice #3 (Step 224). Since no deterioration is shown in the opticaltest signal deterioration state report from the optical node device #3(Step 225), the optical node device #1 sets an optical test path to theoptical node device #4, which is three hops ahead of the optical nodedevice #1 itself (Step 226 and Step 222). In FIG. 83, the optical nodedevice #1 sends the optical test path setting request (PATH) to theoptical node device #4 via the optical node devices #2 and #3. When theoptical node device #4 receives the optical test path setting request(PATH), it ensures the resources required for optical test path settingand sends the optical test path setting completion notification (RESV)to the optical node device #1 via the optical node devices #3 and #2.Accordingly, the optical test path is set between the optical nodedevices #1 and #4.

Subsequently, the optical node device #1 sends an optical test signal(LIGHT) to the set optical test path (Step 223), and receives an opticaltest signal deterioration state report (RESULT) from the optical nodedevice #4 (Step 224). Since no deterioration is shown in the opticaltest signal deterioration state report from the optical node device #4(Step 225), the optical node device #1 sets an optical test path to theoptical node device #5, which is four hops ahead of the optical nodedevice #1 itself (Step 226 and Step 222). In FIG. 83, the optical nodedevice #1 sends the optical test path setting request (PATH) to theoptical node device #5 via the optical node devices #2, #3, and #4. Whenthe optical node device #5 receives the optical test path settingrequest (PATH), it ensures the resources required for optical test pathsetting and sends the optical test path setting completion notification(RESV) to the optical node device #1 via the optical node devices #4,#3, and #2. Accordingly, the optical test path is set between theoptical node devices #1 and #5.

Subsequently, the optical node device #1 sends an optical test signal(LIGHT) to the set optical test path (Step 223), and receives an opticaltest signal deterioration state report (RESULT) from the optical nodedevice #5 (Step 224). Since no deterioration is shown in the opticaltest signal deterioration state report from the optical node device #5(Step 225), the optical node device #1 sets an optical test path to theoptical node device #6, which is five hops ahead of the optical nodedevice #1 itself (Step 226 and Step 222). In FIG. 83, the optical nodedevice #1 sends the optical test path setting request (PATH) to theoptical node device #6 via the optical node devices #2, #3, #4, and #5.When the optical node device #6 receives the optical test path settingrequest (PATH), it ensures the resources required for optical test pathsetting and sends the optical test path setting completion notification(RESV) to the optical node device #1 via the optical node devices #5,#4, #3, and #2. Accordingly, the optical test path is set between theoptical node devices #1 and #6.

Subsequently, the optical node device #1 sends an optical test signal(LIGHT) to the set optical test path (Step 223), and receives an opticaltest signal deterioration state report (RESULT) from the optical nodedevice #6 (Step 224). Deterioration is shown in the optical test signaldeterioration state report from the optical node device #6 (Step 225),so that the optical node device #1 recognizes that the section from theoptical node device #1 itself to the optical node device #5, which isfour hops ahead of the optical node device #1 itself is the 3R section(Step 227).

In this way, in the twenty-eighth embodiment, it is possible to set theoptical test path and recognize the 3R section. In the example of FIG.83, all of the respective optical node devices #1 to #7 comprise a 3Rsection information collection unit 430. However the configuration maybe such that for example every other optical node device comprises it.Moreover, in the present embodiment, in order to facilitate description,the optical test signal was sent to the optical node devices #2 and #3which are not expected to require the 3R relay. However, the sendingprocedure of the optical test signal may be omitted with respect tothese optical node devices #2 and #3. Alternatively, the optical testsignal may be sent to only the optical node devices #5 and #6 which areexpected to require the 3R relay.

Moreover, the 3R section information collection unit 430 stores theinformation of the optical node device for implementing the 3R relayrecognized in this manner. Furthermore, the configuration may be suchthat the 3R section information collection unit 430 advertises theinformation of the optical node device for implementing the 3R relayrecognized in this manner, to the other optical node devices, andreceives the advertisement from the other optical node devices so as tostore the information of the optical node device for implementing the 3Rrelay included in the advertisement together with the information of theoptical node device for implementing the 3R relay recognized by theoptical node device itself. Accordingly, the respective optical nodedevices can store the same 3R section information.

Alternatively, the 3R section information collection unit 430 notifiesthe information of the optical node device for implementing the 3R relayrecognized by the optical node device itself to the network controldevice 410 shown in FIG. 64, so that the network control device 410 canstore the 3R section information of the whole optical network. Then, therespective optical node devices request the network control device 410to provide the 3R section information required by the optical nodedevices themselves and obtain it as necessary, prior to the optical pathsetting, so that the amount of the 3R section information stored in therespective optical node devices can be reduced.

Such a network control device 410 comprises a database comprising: afunction for receiving the information of the optical node device whichimplements the 3R relay from an optical node device constituting theoptical network and updating the 3R section information stored up tonow; and a function for providing a part of or all of the 3R sectioninformation stored according to a request from the optical node device,to this optical node device.

The twenty-eighth embodiment up to here is described on the assumptionof a downstream optical path of the unidirectional optical path or thebi-directional optical path. The following is a description on theassumption of the upstream optical path, with reference to FIG. 85 andFIG. 86. The optical node devices according to the twenty-eighthembodiment comprise the 3R section information collection unit 430 whichsequentially sets an upstream optical test path one hop at a time fromthe next-hop adjacent optical node device to another optical node deviceincluded in a measured link being subjected to the measurement of 3Rsection information when the optical node device itself is the sourcenode. The 3R section information collection unit 430 of the optical nodedevice having this upstream optical test path set, comprises a unitwhich sends an optical test signal to the upstream optical test path.Furthermore, the 3R section information collection unit 430 of theoptical node device where the optical node device itself is the sourcenode, comprises a unit which receives the optical test signal andnotifies the report on the optical test signal deterioration state tothe sender of the optical test signal. The 3R section informationcollection unit 430 of the sender optical node device of the opticaltest signal comprises a unit which recognizes that the optical nodedevice itself is the 3R source node and the 3R destination node of theprevious 3R section on the upstream optical path, if the optical testsignal deterioration state based on this notification satisfies apredetermined deterioration condition. The 3R section informationcollection unit 430 of the optical node device which recognized that theoptical node device itself is the 3R source node and the 3R destinationnode of the previous 3R section on the upstream optical path, comprisesa unit which sequentially sets the upstream optical test path one hop ata time from the next-hop adjacent optical node device to another opticalnode device included in a measured link being subjected to themeasurement of 3R section information, receives the optical test signal,and notifies the report on the optical test signal deterioration stateto the sender of the optical test signal. In practice, each optical nodedevice comprises a 3R section information collection unit 430, and theabove functions of the respective units are activated according to thenecessity for the 3R section information collection of the optical nodedevice itself.

Next is a description of the optical node device according to thetwenty-eighth embodiment. The 3R section information collectingprocedure shown in FIG. 86 is executed by the 3R section informationcollection unit 430. Here is a description of an example of a process inwhich the 3R section information is collected assuming that the opticalnode device #1 is the 3R destination node on the upstream optical path.As shown in FIG. 85, the 3R section information collection unit 430 ofthe optical node device #1 sets the optical test path to the opticalnode device #2, which is one hop ahead of the optical node device #1itself (Step 231 and Step 232). In FIG. 85, the optical node device #1sends an optical test path setting request (PATH) to the optical nodedevice #2. When the optical node device #2 receives the optical testpath setting request (PATH), it ensures the resources required foroptical test path setting and sends the optical test path settingcompletion notification (RESV) to the optical node device #1.Accordingly, the optical test path is set between the optical nodedevices #1 and #2.

Subsequently, the optical node device #1 receives an optical test signal(LIGHT) from the set upstream optical test path (Step 233), and measuresthe deterioration in the optical test signal from the optical nodedevice #2 and reports the measurement result (RESULT) to the opticalnode device #2 (Step 234). Since no deterioration is shown in theoptical test signal from the optical node device #2 (Step 235), theoptical node device #1 sets an optical test path to the optical nodedevice #3, which is two hops ahead of the optical node device itself(Step 236 and Step 232). In FIG. 85, the optical node device #1 sendsthe optical test path setting request (PATH) to the optical node device#3 via the optical node device #2. When the optical node device #3receives the optical test path setting request (PATH), it ensures theresources required for optical test path setting and sends the opticaltest path setting completion notification (RESV) to the optical nodedevice #1 via the optical node device #2. Accordingly, the optical testpath is set between the optical node devices #1 and #3.

Subsequently, the optical node device #1 receives an optical test signal(LIGHT) from the set upstream optical test path (Step 233), and measuresthe deterioration in the optical test signal from the optical nodedevice #3 and reports the measurement result (RESULT) to the opticalnode device #3 (Step 234). Since no deterioration is detected in theoptical test signal from the optical node device #3 (Step 235), theoptical node device #1 sets an optical test path to the optical nodedevice #4, which is three hops ahead of the optical node device #1itself (Step 236 and Step 232). In FIG. 85, the optical node device #1sends the optical test path setting request (PATH) to the optical nodedevice #4 via the optical node devices #2 and #3. When the optical nodedevice #4 receives the optical test path setting request (PATH), itensures the resources required for optical test path setting and sendsthe optical test path setting completion notification (RESV) to theoptical node device #1 via the optical node devices #3 and #2.Accordingly, the optical test path is set between the optical nodedevices #1 and #4.

Subsequently, the optical node device #1 receives an optical test signal(LIGHT) from the set upstream optical test path (Step 233), and measuresthe deterioration in the optical test signal from the optical nodedevice #4 and reports the measurement result (RESULT) to the opticalnode device #4 (Step 234). Since no deterioration is detected in theoptical test signal from the optical node device #4 (Step 235), theoptical node device #1 sets an optical test path to the optical nodedevice #5, which is four hops ahead of the optical node device #1 itself(Step 236 and Step 232). In FIG. 85, the optical node device #1 sendsthe optical test path setting request (PATH) to the optical node device#5 via the optical node devices #2, #3, and #4. When the optical nodedevice #5 receives the optical test path setting request (PATH), itensures the resources required for optical test path setting and sendsthe optical test path setting completion notification (RESV) to theoptical node device #1 via the optical node devices #4, #3, and #2.Accordingly, the optical test path is set between the optical nodedevices #1 and #5.

Subsequently, the optical node device #1 receives an optical test signal(LIGHT) from the set upstream optical test path (Step 233), and measuresthe deterioration in the optical test signal from the optical nodedevice #5 and reports the measurement result (RESULT) to the opticalnode device #5 (Step 234). Since no deterioration is detected in theoptical test signal from the optical node device #5 (Step 235), theoptical node device #1 sets an optical test path to the optical nodedevice #6, which is five hops ahead of the optical node device #1 itself(Step 236 and Step 232). In FIG. 85, the optical node device #1 sendsthe optical test path setting request (PATH) to the optical node device#6 via the optical node devices #2, #3, #4, and #5. When the opticalnode device #6 receives the optical test path setting request (PATH), itensures the resources required for optical test path setting and sendsthe optical test path setting completion notification (RESV) to theoptical node device #1 via the optical node devices #5, #4, #3, and #2.Accordingly, the optical test path is set between the optical nodedevices #1 and #6.

Subsequently, the optical node device #1 receives an optical test signal(LIGHT) from the set upstream optical test path (Step 233), and measuresthe deterioration in the optical test signal from the optical nodedevice #6 and reports the measurement result (RESULT) to the opticalnode device #6 (Step 234). Deterioration is detected in the optical testsignal from the optical node device #6 (Step 235), so that the opticalnode device #1 recognizes that the section from the optical node device#1 itself to the optical node device #5, which is four hops ahead of theoptical node device #1 itself is the 3R section (Step 237).

In the example of FIG. 85, when the optical node device #1 receives theoptical test signal of the optical node devices #2 to #5 arriving fromthe upstream optical path, even if deterioration is not detected, thereport is performed (RESULT). However, this report has only the role ofensuring reception confirmation of the optical test signal, so that thisreporting procedure may be omitted.

In this way, in the twenty-eighth embodiment, it is possible to set theoptical test path and recognize the 3R section. In the example of FIG.85, all of the respective optical node devices #1 to #7 comprise a 3Rsection information collection unit 430. However the configuration maybe such that for example every other optical node device comprises it.Moreover, in the present embodiment, in order to facilitate description,the optical test signal was sent to the optical node devices #2 and #3which are not expected to require the 3R relay. However, the sendingprocedure of the optical test signal may be omitted with respect tothese optical node devices #2 and #3. Alternatively, the optical testsignal may be sent to only the optical node devices #5 and #6 which areexpected to require the 3R relay.

Moreover, the 3R section information collection unit 430 stores theinformation of the optical node device for implementing the 3R relayrecognized in this manner. Furthermore, the configuration may be suchthat the 3R section information collection unit 430 advertises theinformation of the optical node device for implementing the 3R relayrecognized in this manner, to the other optical node devices, andreceives the advertisement from the other optical node devices so as tostore the information of the optical node device for implementing the 3Rrelay included in the advertisement together with the information of theoptical node device for implementing the 3R relay recognized by theoptical node device itself. Accordingly, the respective optical nodedevices can store the same 3R section information.

Alternatively, the 3R section information collection unit 430 notifiesthe information of the optical node device for implementing the 3R relayrecognized by the optical node device itself to the network controldevice 410 shown in FIG. 64, so that the network control device 410 canstore the 3R section information of the whole optical network. Then, therespective optical node devices request the network control device 410to provide the 3R section information required by the optical nodedevices themselves and obtain it as necessary, prior to the optical pathsetting, so that the amount of the 3R section information stored in therespective optical node devices can be reduced.

Such a network control device 410 comprises a database comprising: afunction for receiving the information of the optical node device whichimplements the 3R relay from an optical node device constituting theoptical network and updating the 3R section information stored up tonow; and a function for providing a part of or all of the 3R sectioninformation stored according to a request from the optical node device,to this optical node device.

Twenty-ninth Embodiment

Since the basic concept of the twenty-ninth embodiment is similar tothat of the twentieth embodiment, the optical node device of the presentembodiment is described with reference to FIG. 60 to FIG. 63 used forthe twentieth embodiment. However, as described below, the detailedoperation in the units shown in FIG. 60 to FIG. 63 is different fromthat of the twentieth embodiment. FIG. 60 and FIG. 62 show concepts of3R section information collection in the optical node devices accordingto the twenty-ninth embodiment. FIG. 61 and FIG. 63 are block diagramsof the optical node device according to the twenty-ninth embodiment.

As shown in FIG. 61, the optical node device according to thetwenty-ninth embodiment comprises: a Q-value storing unit 234 whichstores a value Q, preset for each link based on the optical signaldeterioration characteristic in the link between the optical node deviceitself and the adjacent node; a P-value sending unit 232 which transmitsan initial value P of the minuend value to the next-hop adjacent opticalnode device if the optical node device itself is the source node; aQ-value subtraction unit 235 which calculates (P−Q) or (P′−Q) if theoptical node device itself receives the initial value P or a minuendvalue P′ which has already been reduced from the initial value P, fromthe previous-hop adjacent optical node device; and a comparison unit 236which compares the calculation result by this Q-value subtraction unit235 with a threshold, then transmits the calculation result to thenext-hop adjacent optical node device, if the calculation result isgreater than the threshold, or recognizes that the optical node deviceitself is the 3R destination node using the optical node device thatsent the initial value P of the minuend value as the 3R source node, ifthe calculation result is less than or equal to the threshold. TheP-value sending unit 232 recognizes that the optical node device itselfis the 3R destination node, and transmits the initial value P of theminuend value to the next-hop adjacent optical node device using theoptical node device itself as the 3R source node, if the optical nodedevice itself is not the destination node of the optical path on whichthe minuend value is transmitted.

Next is a description of the operation of the optical node deviceaccording to the twenty-ninth embodiment. The Q-value generation unit233 generates a Q-value based on the result for the degree of opticalsignal deterioration of the link connected to the optical node deviceitself, with reference to a parameter table 240 and a degree ofdeterioration table 250. The Q-value is a constant which is determinedin proportion to the degree of deterioration, and is provided for eachlink. Moreover, the Q-value is set with respect to the initial value P.For example, if the degree of deterioration of the optical signal of theoptical node device itself is considered using the optical signalintensity and the light noise, in the case where the optical signal sentfrom the 3R source node is attenuated to half intensity and the errorrate of the optical signal sent from the 3R source node is increased todouble, the Q-value is set to 50 if the initial value P is 100.

This Q-value is subtracted at each time of passing through the opticalnode device, and it is found that the optical node device having thesubtraction result less than or equal to the threshold is the 3Rdestination node. In this manner, it recognizes that the optical nodedevice itself is the 3R destination node if the optical node device thatsent the initial value P is used as the 3R source node, and stores therecognition result as the section information. Alternatively, byadvertising this recognition result to other optical node devices or thenetwork control device as well as storing the recognition result, therespective optical node devices can share the same 3R sectioninformation.

Furthermore, if it recognizes the optical node device itself to be the3R destination node and not the destination node of the measured opticalpath, an initial value P is newly sent using the optical node deviceitself as the 3R source node.

In this manner, the 3R section information from the source node to thedestination node can be collected. Moreover, the collection of the 3Rsection information can be performed in the process of optical pathsetting. That is, if the initial value P is loaded into the optical pathsetting request, the optical path setting procedure can be executedwhile determining whether or not the optical node device itself is the3R destination node in the respective optical node devices whichreceived the optical path setting request.

The twenty-ninth embodiment up to here is described on the assumption ofa downstream optical path of the unidirectional optical path or thebi-directional optical path. The following is a description on theassumption of the upstream optical path of the bi-directional opticalpath with reference to FIG. 62 and FIG. 63.

As shown in FIG. 63, the optical node device according to thetwenty-ninth embodiment comprises: a q-value storing unit 334 whichstores a value q, preset for each link based on the optical signaldeterioration characteristic in the link between the optical node deviceitself and the adjacent node; a p-value sending unit 332 which transmitsan initial value p of the augend to the next-hop adjacent optical nodedevice if the optical node device itself is the source node; a q-valueaddition unit 335 which calculates (p+q) or (p′+q) if the optical nodedevice itself receives the initial value p or an augend value p′, whichhas already been increased from the initial value p, from theprevious-hop adjacent optical node device; and a comparison unit 336which compares the calculation result by this q-value addition unit 335with the threshold, then transmits the calculation result to thenext-hop adjacent optical node device, if the calculation result is lessthan the threshold, or recognizes that the optical node device itself isthe 3R source node using the optical node device that sent the initialvalue p of the augend as the 3R destination node on the upstream opticalpath, if calculation result is greater than or equal to the threshold.The p-value sending unit 332 recognizes that the optical node deviceitself is the 3R source node on the upstream optical path and transmitsthe initial value p of the augend to the next-hop adjacent optical nodedevice using the optical node device itself as the 3R destination nodeon the upstream optical path, if the optical node device itself is notthe destination node of the optical path on which the augend istransmitted.

Next is a description of the operation of the optical node deviceaccording to the twenty-ninth embodiment. The q-value generation unit333 generates a q-value based on the result for the degree of opticalsignal deterioration of the link connected to the optical node deviceitself, with reference to the parameter table 240 and the degree ofdeterioration table 250. The q-value is a constant which is determinedin proportion to the degree of deterioration, and is provided for eachlink. Moreover, the q-value is set similarly to the case of the Q-valueof the downstream optical path.

This q-value is added at each time of passing through the optical nodedevice, and it is found that the optical node device having the additionresult greater than or equal to the threshold is the 3R source node onthe upstream optical path. In this manner, it recognizes that theoptical node device itself is the 3R source node if the optical nodedevice that sent the initial value p is used as the 3R destination nodeon the upstream optical path, and stores the recognition result as the3R section information. Alternatively, by advertising this recognitionresult to other optical node devices or the network control device aswell as storing the recognition result, the respective optical nodedevices can share the same 3R section information.

Furthermore, if it recognizes that the optical node device itself is the3R source node on the upstream optical path, and the optical node deviceitself is not the destination node of the measured optical path, thenassuming that the optical node device itself is the 3R destination nodeon the upstream optical path, the initial value p is newly sent.

The p value is “0” in the twenty-ninth embodiment; however the p-valuemay be set in consideration of various conditions. For example, thelength of the 3R section generated can be adjusted by the p-value withina range of the maximum length of the 3R section. That is, if thethreshold is fixed, assuming that the p-value is a negative integer, thevalue capable of being added is increased more than in the case wherethe p-value is set to “0”, enabling the 3R section to be set longer.Conversely, assuming that the p-value is a positive integer, the valuecapable of being added is decreased compared to the case where thep-value is set to “0”, enabling the 3R section to be set shorter.

In this manner, the 3R section information from the source node to thedestination node can be collected. Moreover, the collection of the 3Rsection information can be performed in the process of optical pathsetting. That is, if the initial value p is loaded into the optical pathsetting request, the optical path setting procedure can be executedwhile determining whether or not the optical node device itself is the3R source node on the upstream optical path in the respective opticalnode devices which received the optical path setting request.

In the twenty-first to twenty-ninth embodiments, in order to facilitatedescription, the case on the assumption of the downstream optical pathand the case on the assumption of the upstream optical path wereseparately described. However, in practice, by performing them at thesame time, the 3R section information can be generated both on theupstream and downstream bi-directional optical paths at the same time.

INDUSTRIAL APPLICABILITY

The present invention is used in optical networks that switch opticalsignals. In particular, it relates to optical networks including opticalnode devices for implementing 3R relay. According to the presentinvention, it is possible to constitute an economical optical network byeffectively using network resources by using the minimum number of, orminimum capacity of 3R repeaters.

1. An optical node device that switches an optical signal, comprising: arequesting unit which is configured to request that a network controldevice provide the optical node device itself with 3R sectioninformation corresponding to topology information of an optical networkto which the optical node device itself belongs, the network controldevice managing the optical network; and an acquiring unit which isconfigured to acquire the 3R section information, which is provided fromthe network control device, wherein the acquiring unit is provided witha unit which is configured to select and store at least a portion ofinformation associated with the optical node device itself from the 3Rsection information acquired.
 2. An optical node device that switches anoptical signal, comprising: a requesting unit which is configured torequest that a network control device provide the optical node deviceitself with 3R section information corresponding to topology informationof an optical network to which the optical node device itself belongs,the network control device managing the optical network; and anacquiring unit which is configured to acquire the 3R sectioninformation, which is provided from the network control device, whereina preset section in which data transmission is possible without 3R relayis defined as a 3R section, and the optical node device is furtherprovided with a unit which is configured to store the 3R sectioninformation acquired by the acquiring unit, and to advertise the 3Rsection information to other optical node devices.
 3. An optical nodedevice that switches an optical signal, comprising: a requesting unitwhich is configured to request that a network control device provide theoptical node device itself with 3R section information corresponding totopology information of an optical network to which the optical nodedevice itself belongs, the network control device managing the opticalnetwork; and an acquiring unit which is configured to acquire the 3Rsection information, which is provided from the network control device,wherein a preset section in which data transmission is possible without3R relay is defined as a 3R section, an optical node device, being asource of a setting request for an optical path, is defined as a sourcenode, and an optical node device at an end point of the optical path isdefined as a destination node, the requesting unit is configured torequest the network control device for the 3R section information whenthe optical node device itself is a source node, and the optical nodedevice is further provided with a unit which is configured to store the3R section information acquired by the acquiring unit, and to transmitthe 3R section information to other optical node devices contained in anoptical path up to the destination node when the optical node deviceitself is used as the source node.
 4. An optical node device thatswitches an optical signal, comprising: a requesting unit which isconfigured to request that a network control device provide the opticalnode device itself with 3R section information corresponding to topologyinformation of an optical network to which the optical node deviceitself belongs, the network control device managing the optical network;and an acquiring unit which is configured to acquire the 3R sectioninformation, which is provided from the network control device, whereina preset section in which data transmission is possible without 3R relayis defined as a 3R section, an optical node device, being a source of asetting request for an optical path, is defined as a source node, and anoptical node device at an end point of the optical path is defined as adestination node, the requesting unit is configured to request thenetwork control device for the 3R section information when the opticalnode device itself is a source node, the optical node device is furtherprovided with: an advertising unit which is configured to store the 3Rsection information acquired by the acquiring unit, and to advertise the3R section information to other optical node devices; a determining unitwhich is configured to determine whether an advertisement by theadvertising unit is associated with an optical path that passes throughthe optical node device itself; a unit which is configured to discardthe advertisement when a determination result of the determining unitindicates that the advertisement is not associated with the optical paththat passes through the optical node device itself; and a unit which isconfigured to store contents of the advertisement when the determinationresult of the determining unit indicates that the advertisement isassociated with the optical path which passes through the optical nodedevice itself.